Variable resistive element, and its manufacturing method

ABSTRACT

A variable resistive element comprising a configuration that an area of an electrically contributing region of a variable resistor body is finer than that constrained by an upper electrode or a lower electrode and its manufacturing method are provided. A bump electrode material is formed on a lower electrode arranged on a base substrate. The bump electrode material is contacted to a variable resistor body at a surface different from a contact surface to the lower electrode. The variable resistor body is contacted to an upper electrode at a surface different from a contact surface to the bump electrode material. Thus, a cross point region between the bump electrode material (the variable resistor body) and the upper electrode becomes an electrically contributing region of the variable resistor body, and then an area thereof can be reduced compared with that of the region regarding the conventional variable resistive element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Phase filing under 35 U.S.C. §371 ofInternational Application No. PCT/JP2007/053358 filed on Feb. 23, 2007,and which claims priority to Japanese Patent Application No. 2006-125432filed on Apr. 28, 2006.

TECHNICAL FIELD

The present invention relates to a variable resistive element comprisingan electrode, another electrode and a variable resistor body, whereinthe variable resistor body is provided between the one electrode and theother electrode, and an electrical resistance of the variable resistiveelement is changed by applying a voltage pulse between both of theelectrodes, and relates to its manufacturing method.

BACKGROUND ART

In recent years, a variety of device structures are presented, such as aferroelectric random access memory (FeRAM), a magnetic RAM (MRAM), aphase change RAM (PRAM), or the like, as a next generation nonvolatileRAM (NVRAM) for fast operation possible taking the place of a flashmemory. And then a keen development race is performed from points ofview of a higher performance, a higher reliability, a lower cost and ahigher integrity of manufacturing processes. However, each of such thecurrent memory devices has both advantages and disadvantagesrespectively, and it is still a long way away from realizing an idealuniversal memory having every advantage of a static RAM (SRAM), adynamic RAM (DRAM) and the flash memory.

On the contrary to such the conventional technologies, there ispresented a nonvolatile resistive random access memory (RRAM) using avariable resistive element wherein an electrical resistance of thevariable resistive element is changed reversibly by applying a voltagepulse thereto. Here, a configuration of such the conventional variableresistive element is shown in FIG. 42.

Such the variable resistive element comprising the conventionalconfiguration includes a structure that a lower electrode 203, avariable resistor body 202 and an upper electrode 201 are layered inorder, and has a property that a resistance value is changed reversiblyby applying the voltage pulse between the upper electrode 201 and thelower electrode 203, as shown in FIG. 42. And then it comprises aconfiguration for being able to realize a novel nonvolatilesemiconductor memory device by reading out the resistance value to bechanged by such the operation of reversible changing in electricalresistance (referred to as a switching operation hereinafter).

Such the nonvolatile semiconductor memory device is comprised by forminga memory cell array with arranging each of a plurality of memory cellscomprising a variable resistive element for each in a row direction anda column direction as a matrix form, and by arranging peripheralcircuits to control programming, erasing and reading out operations foreach of the memory cell in such the memory cell array. Moreover, forsuch the memory cell, there is provided such as a memory cell comprisedof one selective transistor (T) and one variable resistive element (R)as it is called an 1T/1R type, a memory cell comprised of one variableresistive element (R) as it is called an 1R type, or the like, from apoint of view of configuration element difference thereof. Here, aconfiguration example of the memory cell of 1T/1R type is shown in FIG.43.

FIG. 43 is an equivalent circuit diagram showing one configurationexample of a memory cell array using memory cells of 1T/1R type. In eachof the memory cells, a gate electrode of the selective transistor (T) isconnected to each of word lines WL1 to WLn respectively, and a sourceregion of the selective transistor (T) is connected to each of sourcelines SL1 to SLn respectively, as (n) is a natural number. Moreover, oneelectrode of the variable resistive element (R) in each of the memorycells is connected to a drain region of the selective transistor (T)respectively, and another electrode of the variable resistive element(R) is connected to each of bit lines BL1 to BLm respectively, as (m) isa natural number.

Moreover, each of the word lines WL1 to WLn is connected to a word linedecoder 206 respectively, each of the source lines SL1 to SLn isconnected to a source line decoder 207 respectively, and each of the bitlines BL1 to BLm is connected to a bit line decoder 205 respectively.Furthermore, there is provided a configuration that a predetermined bitline, word line, or source line is to be selected corresponding to anaddress input (not shown) for a programming operation, an erasingoperation, or a reading out operation respectively, regarding apredetermined memory cell in a memory cell array 204.

FIG. 44 is a cross sectional pattern diagram showing one memory cellcomprising the memory cell array 204 as shown in FIG. 43. According tothe present configuration, one memory cell is to be comprised of oneselective transistor (T) and one variable resistive element (R).Moreover, the selective transistor (T) is comprised of a gate insulatingfilm 213, a gate electrode 214, a drain diffusion layer region 215 and asource diffusion layer region 216, and then it is formed on a topsurface of a semiconductor substrate 211 where an element isolationregion 212 is formed. Furthermore, the variable resistive element (R) iscomprised of a lower electrode 218, a variable resistor body 219 and anupper electrode 220. According to the present embodiment, the variableresistor body 219 is arranged inside an open part arranged between thelower electrode 218 and the upper electrode 220, however, it may alsoavailable that such the elements are arranged in order from the top tobe a terraced structure as shown in FIG. 42.

Moreover, the gate electrode 214 in the transistor (T) comprises a wordline, and a source line wiring 224 is electrically connected to thesource diffusion layer region 216 in the transistor (T) via a contactplug 222. Furthermore, a bit line wiring 223 is electrically connectedto the upper electrode 220 in the variable resistive element (R) via acontact plug 221, meanwhile, the lower electrode 218 is electricallyconnected to the drain diffusion layer region 215 in the transistor (T)via a contact plug 217.

Thus, there is provided a configuration that the transistor becomes tobe an on state in the selected memory cell using a change in electricpotential of the word line, and it becomes able to program or eraseselectively regarding the variable resistive element (R) in the selectedmemory cell using the change in electric potential of the bit line, byarranging the selective transistor (T) and the variable resistiveelement (R) as a series connection.

FIG. 45 is an equivalent circuit diagram showing one configurationexample of a memory cell array using memory cells of 1R type. Each ofthe memory cells consists of one variable resistive element (R), whereinone electrode in each of the variable resistive elements (R) isconnected to each of word lines WL1 to WLn respectively, and anotherelectrode is connected to each of bit lines BL1 to BLm respectively.Moreover, each of the word lines WL1 to WLn is connected to a word linedecoder 233 respectively, and each of the bit lines BL1 to BLm isconnected to a bit line decoder 232 respectively. Furthermore, there isprovided a configuration that a predetermined bit line or word line isto be selected corresponding to an address input (not shown) for aprogramming operation, an erasing operation, or a reading out operationrespectively, regarding a predetermined memory cell in a memory cellarray 231.

FIG. 46 is a diagrammatic perspective view schematically showing oneexample of a memory cell comprising the memory cell array 231 shown inFIG. 45. As shown in FIG. 46, an upper electrode wiring 243 and a lowerelectrode wiring 241 are arranged for crossing respectively, and thenone of the electrode wirings forms a bit line, and the other forms aword line. Moreover, there is provided a configuration that a variableresistor body 242 is arranged in a region at the intersection of theelectrode wirings as it is normally called a cross point. Here, theupper electrode wiring 243 and the resistor body 242 are manufactured ina similar shape according to the example shown in FIG. 46, however, apart electrically contributing to a switching operation in the variableresistor body 242 is to be the region as the cross point at theintersection of the upper electrode wiring 243 and the lower electrodewiring 241.

Regarding a variable resistor body material to be used for the abovementioned variable resistor body 219 shown in FIG. 44 or the variableresistor body 242 shown in FIG. 46, there is disclosed a technology inthe following patent document 1 and a nonpatent document 1 by ShangquingLiu, Alex Ignatiev et al., University of Houston, USA, that anelectrical resistance is changed reversibly by applying a voltage pulseto a perovskite material known for having a colossal magnetoresistanceeffect. Such the technology is extremely revolutionary as a change inelectrical resistance appears in a wide range of several orders ofmagnitude even at room temperature without applying a magnetic field,even with using the perovskite material known for having the colossalmagnetoresistance effect. Here, a crystalline praseodymium calciummanganese oxide (PCMO: Pr_(1-x)Ca_(x)MnO₃) film as a perovskite-typeoxide is used as the material for variable resistor body according tothe element structure embodied in the patent document 1.

Moreover, according to a nonpatent document 2 and a patent document 2,it is known that an oxide of transition metal elements, such as atitanium oxide (TiO₂) film, a nickel oxide (NiO) film, a zinc oxide(ZnO) film, a niobium oxide (Nb₂O₅) film, or the like, shows areversible change in electrical resistance as other materials forvariable resistor body. Furthermore, there is reported in detail in anonpatent document 3 regarding a phenomenon in a switching operationusing the NiO film among such the materials.

-   Patent document 1: U.S. Pat. No. 6,204,139-   Nonpatent document 1: S. Q. Liu et al., “Electric-pulse-induced    reversible Resistance change effect in magnetoresistive films”,    Applied Physics Letters, vol. 76, pp. 2749-2751 (2000)-   Nonpatent document 2: H. Pagnia et al., “Bistable Switching in    Electroformed Metal-Insulator-Metal Devices”, Phys. Stat. Sol. (a),    vol. 108, pp. 11-65 (1988)-   Patent document 2: Japanese published patent publication 2002-537627-   Nonpatent document 3: I. G. Baek et al., “Highly Scalable    Non-volatile Resistive Memory using Simple Binary Oxide Driven by    Asymmetric Unipolar Voltage Pulses”, IEDM 04, pp. 587-590 (2004)

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

At the period of writing operation regarding data in the above mentionednonvolatile memory device, that is to say, in the period from startingapplying an electric pulse between the upper electrode and the lowerelectrode to reaching a predetermined resistance value regarding thevariable resistor body, a transient current flows through the variableresistive element (R). Such the current is called a programming currentor an erasing current corresponding to a direction of change regardingthe electrical resistance respectively. For example, in the case ofusing the oxide of transition metal element as the material for variableresistor body, there is reported in the nonpatent document 3 wherein theNiO film is used that the programming current and the erasing currentfor an electrode surface area of 0.3×0.7 □m² are approximately 1 mArespectively. Both amounts of such the currents correspond to an area ofan electrically contributing region in the variable resistor body, andthen it is able to suppress the programming current and the erasingcurrent by decreasing such the area, and it becomes able to suppress acurrent consumption in the nonvolatile memory device as well.

Moreover, it is able to manufacture a memory element reproducibly with astable switching operation in the case of excellent crystalline for thevariable resistor body generally, however, an improvement of such thecrystalline cannot help but cause a relative decrease in a resistancevalue regarding the variable resistor body. Moreover, the resistancevalue regarding the variable resistor body is inversely proportional toan area of the electrically contributing region in the variable resistorbody, and then the electrical resistance of the variable resistiveelement (R) becomes smaller in the case of such the area becominglarger. In such the case, regarding the memory cell of 1T/1R type, thereis occurred a problem, such as a programming impossible or the like,because a sufficient voltage is not applied to the variable resistorbody in the case of the electrical resistance of the variable resistiveelement (R) becoming considerably smaller than an on resistance of acontrol transistor (T). Furthermore, even for the memory cell of 1Rtype, a parasitic current flowing through any other cells except theselected cell becomes larger, that are connected to a selected bitwiring or word wiring, and then there is occurred the similar problem asthe programming impossible due to an applying voltage becominginsufficient.

Therefore, it is able to suppress the current consumption and it becomespossible to manufacture the memory element reproducibly with a stableswitching operation without becoming the programming impossible if it isable to manufacture in a smaller size regarding the area of theelectrically contributing region in the variable resistor body. However,regarding the above mentioned conventional memory cell, the area of theelectrically contributing region in the variable resistor body isspecified, for example, by an area of the variable resistor body 219part shown in FIG. 44 or by a size of the upper electrode 201 shown inFIG. 42 regarding the memory cell of 1T/1R type, and by an area of thecross point region at the intersection of the upper electrode wiring 243and the lower electrode wiring 241 shown in FIG. 46 regarding the memorycell of 1R type. Hence, the area of the electrically contributing regionin the variable resistor body is constrained by formative areas for suchthe electrodes and the like. And then the area to be able to realize hasa lower limit against reducing thereof.

The present invention is presented with having regard to the abovementioned problems, and an object is to provide a variable resistiveelement comprising a configuration that an area of an electricallycontributing region in a variable resistor body is finer than the areasspecified by the upper electrode, the lower electrode and the like, andto provide its manufacturing method.

Means for Solving the Problem

For achieving the above mentioned object, a variable resistive elementaccording to a first feature of the present invention comprises: avariable resistor body provided between two electrodes, in which anelectrical resistance of between the two electrodes is changed byapplying a voltage pulse between the two electrodes; and a bumpelectrode material contacting to either one of the two electrodes andextending toward the other one of the electrodes, wherein the variableresistor body is formed between the bump electrode material and theother one of the electrodes.

According to the first feature construction regarding the variableresistive element according to the present invention, there is providedthe configuration in that the bump electrode material contacting toeither one of the two electrodes is provided and such the bump electrodematerial is extended toward the other one of the electrodes, further,the variable resistor body is provided at an apical part thereof, andthen it is to be connected to the other one of the electrodes via suchthe variable resistor body. Hence, it is able to obtain an area of anelectrically contributing region of a variable resistor body smallerthan a formative area specified by manufacturing processes. Here, it isable to form the bump electrode material with an area of a fine regionby using a self-aligned process, without depending only on a fineprocessing which is constrained by an exposure technology. Thus, itbecomes able to reduce the current consumption at the period ofprogramming or erasing thereby, and it becomes able to manufacture amemory element reproducibly with a stable switching operation withoutoccurring a programming impossible due to a low electrical resistancethereof.

Moreover, the variable resistive element according to the presentinvention is characterized as a second feature in addition to the firstfeature construction in that the bump electrode material is extendedalong a sidewall of an insulating film formed between the twoelectrodes, and formed so as to project toward the other one of the twoelectrodes with an annular or a plurally-separated linear shape.

Further, the variable resistive element according to the presentinvention is characterized as a third feature in addition to the firstfeature construction in that the bump electrode material is extendedalong a sidewall of an insulating film formed between the twoelectrodes, and formed so as to project toward the other one of the twoelectrodes with one linear shape.

Still further, the variable resistive element according to the presentinvention is characterized as a fourth feature in addition to the secondor the third feature construction in that the insulating film comprisesan open part to expose whole or a part of a top surface of a lowerelectrode as the electrode formed at a lower region regarding the twoelectrodes, and the bump electrode material is extended along an innersidewall of the open part.

Still further, the variable resistive element according to the presentinvention is characterized as a fifth feature in addition to the secondor the third feature construction by further comprising the insulatingfilm on the lower electrode as the electrode formed at the lower regionregarding the two electrodes, wherein the bump electrode material isextended along an outer sidewall of the insulating film.

Still further, the variable resistive element according to the presentinvention is characterized as a sixth feature in addition to the firstfeature construction by further comprising: a first bump electrodematerial contacting to either one of the two electrodes and extendingtoward the other one of the two electrodes along a sidewall of a firstinsulating film formed between the two electrodes; and a second bumpelectrode material contacting to the other one of the two electrodes andextending toward the one of the two electrodes along a sidewall of asecond insulating film formed between the two electrodes, wherein thevariable resistor body is formed between the first bump electrode andthe second bump electrode.

Still further, the variable resistive element according to the presentinvention is characterized as a seventh feature in addition to any oneof the feature constructions from the first trough the sixth in that thelower electrode as the electrode formed at the lower region regardingthe two electrodes is a diffusion layer formed on a semiconductorsubstrate.

Still further, the variable resistive element according to the presentinvention is characterized as an eighth feature in addition to the firstfeature construction by further comprising a base insulating filmdeposited in parallel to a surface of a substrate, wherein the bumpelectrode material is formed along a top surface of the base insulatingfilm, either one of the two electrodes is formed on a top surface of thebump electrode material, the other one of the two electrodes is formedon the top surface of the base insulating film, and the variableresistor body is formed between the bump electrode material and theother one of the two electrodes.

Still further, the variable resistive element according to the presentinvention is characterized as a ninth feature in addition to any one ofthe feature constructions from the first trough the eighth in that thebump electrode material is formed using a transition metal or a nitrideof a transition metal element.

Furthermore, the variable resistive element according to the presentinvention is characterized as a tenth feature in addition to the ninthfeature construction in that the bump electrode material is a titaniumnitride.

According to the tenth feature construction regarding the variableresistive element according to the present invention, it becomes easyfor designing processes because it is available to use a titanium basedmaterial for the bump electrode material, which has been conventionallyused in general purpose in semiconductor processes.

Moreover, the variable resistive element according to the presentinvention is characterized as an eleventh feature in addition to any oneof the feature constructions from the first through the tenth in thatthe variable resistor body is formed by oxidizing a part of the bumpelectrode material.

According to the eleventh feature construction regarding the variableresistive element according to the present invention, it is able to forma variable resistor body film by thermal processing steps of oxidationas a general process in manufacturing processes for semiconductor, andthen it is possible to realize with using a conventional equipment as itis not required a particular equipment for a deposition of such thefilm.

Moreover, for achieving the above mentioned object, a variable resistiveelement according to a twelfth feature of the present inventioncomprises a variable resistor body provided between two electrodes, inwhich the electrical resistance of between the two electrodes is changedby applying a voltage pulse between the two electrodes, wherein a linewidth of a contact surface of between the variable resistor body and atleast one of the two electrodes is formed to be narrower than the linewidth of any of the two electrodes.

Further, for achieving the above mentioned object, a variable resistiveelement according to a thirteenth feature of the present inventioncomprises a variable resistor body provided between two electrodes, inwhich the electrical resistance of between the two electrodes is changedby applying a voltage pulse between the two electrodes, wherein a linewidth of a contact surface of between the variable resistor body and atleast one of the two electrodes is formed to be smaller than a value ofa film thickness for any of the two electrodes.

According to the twelfth or the thirteenth feature constructionregarding the variable resistive element according to the presentinvention, it is able to obtain an area of an electrically contributingregion of a variable resistor body smaller than a formative areaspecified by manufacturing processes.

Moreover, the variable resistive element according to the presentinvention is characterized as a fourteenth feature in addition to thetwelfth or the thirteenth feature construction in that a shape of acontact surface of between the variable resistor body and at least oneof the two electrodes is an annular or a plurally-separated linearshape.

Further, the variable resistive element according to the presentinvention is characterized as a fifteenth feature in addition to thetwelfth or the thirteenth feature construction in that a shape of acontact surface of between the variable resistor body and at least oneof the two electrodes is one linear shape.

Still further, the variable resistive element according to the presentinvention is characterized as a sixteenth feature in addition to any oneof the feature constructions from the twelfth through the fifteenth inthat a planar shape of the variable resistor body in each of thevariable resistive elements is an annular or a plurally-separated linearshape.

According to the sixteenth feature construction regarding the variableresistive element according to the present invention, it is able toobtain an area of an electrically contributing region of a variableresistor body smaller than a formative area specified by manufacturingprocesses.

Moreover, the variable resistive element according to the presentinvention is characterized as a seventeenth feature in addition to anyone of the feature constructions from the twelfth through the fifteenthin that a planar shape of the variable resistor body in each of thevariable resistive elements is one linear shape.

Further, the variable resistive element according to the presentinvention is characterized as an eighteenth feature in addition to anyone of the feature constructions from the first trough the seventeenthin that the variable resistor body is formed of an oxide of a transitionmetal element or an oxynitride of a transition metal element.

Still further, the variable resistive element according to the presentinvention is characterized as a nineteenth feature in addition to theeighteenth feature construction in that the variable resistor body is atitanium oxide or a titanium oxynitride.

According to the nineteenth feature construction regarding the variableresistive element according to the present invention, it becomes easyfor designing processes because it is available to use a titanium basedmaterial for the variable resistor body, which has been conventionallyused in general purpose in semiconductor processes.

Moreover, for achieving the above mentioned object, a manufacturingmethod for a variable resistive element according to a first feature ofthe present invention is a manufacturing method for the variableresistive element comprising the first feature construction or thesecond feature construction, comprises: a first step of forming a lowerelectrode as the electrode to be formed at a lower region regarding thetwo electrodes by depositing an electrode material onto a substrate tolayer a first electrode film; a second step of forming a firstinsulating film on the lower electrode, the first insulating film havingan open part reaching a top surface of the lower electrode; a third stepof forming a bump electrode material contacting to at least a partialregion of the lower electrode and extending upward along an innersidewall of the open part formed at the second step; a fourth step offorming the variable resistor body at an apical part of the bumpelectrode material; and a fifth step of forming an upper electrode to beformed at an upper region regarding the two electrodes by depositing anelectrode material to layer a second electrode film.

According to the first feature regarding the manufacturing method for avariable resistive element according to the present invention, thevariable resistor body is formed at the apical part of the bumpelectrode material extending from the lower electrode in a directiontoward the upper electrode, and then the bump electrode material and theupper electrode are to be connected via the variable resistor body. Thatis to say, it becomes able to manufacture a variable resistive elementwith being reduced an area of electrically contributing region of avariable resistor body.

Here, the first step may comprise the steps of depositing the firstelectrode film configuring the lower electrode, depositing a secondinsulating film onto the first electrode film, and processing the firstelectrode film and the second insulating film.

Moreover, the second step may comprise the steps of depositing the firstinsulating film, flattening the first insulating film until a topsurface of the second insulating film becomes exposed, and forming theopen part in the first insulating film so that the open part penetratesit and reaches a top surface of the lower electrode.

Further, the manufacturing method for a variable resistive elementaccording to the present invention is characterized as a second featurein addition to the first feature in that the third step comprises thesteps of: forming an electrode film for a bump electrode material bydepositing an electrically conductive material onto the open part andthe first insulating film; depositing a third insulating film onto theelectrode film for the bump electrode material; removing the thirdinsulating film until a top surface of the electrode film for the bumpelectrode material is exposed; and forming the bump electrode materialconnecting to the lower electrode inside the open part by removing theelectrode film for the bump electrode material layered at a region otherthan a region on the open part.

Still further, the manufacturing method for a variable resistive elementaccording to the present invention is characterized as a third featurein addition to the first feature in that the third step furthercomprises: a sixth step of forming an electrode film for a bumpelectrode material by depositing an electrically conductive materialonto the open part and the first insulating film; and a step of formingthe bump electrode material along a sidewall of the open part byremoving the electrode film for the bump electrode material layered onthe first insulating film.

Still further, the manufacturing method for a variable resistive elementaccording to the present invention is characterized as a fourth featurein addition to the third feature in that the sixth step includesdepositing the electrode film for the bump electrode material inside theopen part so that a film thickness of the electrode film for the bumpelectrode material becomes thinner toward a top surface of the lowerelectrode.

Furthermore, the manufacturing method for a variable resistive elementaccording to the present invention is characterized as a fifth featurein addition to the fourth feature in that the fourth step comprises astep of forming a third insulating film on the open part and the firstinsulating film, and the step of forming the third insulating filmincludes forming the variable resistor body by oxidizing a region of thebump electrode material formed along the sidewall of the open part atthe third step, the region having a thin film thickness in a vicinity ofa top surface of the lower electrode.

Moreover, for achieving the above mentioned object, a manufacturingmethod for a variable resistive element according to a sixth feature ofthe present invention is a manufacturing method for the variableresistive element comprising the first feature construction or thesecond feature construction, and comprises: a first step of forming alower electrode as an electrode to be formed at a lower region regardingthe two electrodes by depositing the first electrode film, which is tobe the lower electrode, onto a substrate, by depositing a firstinsulating film onto the first electrode film, and by processing thefirst electrode film and the first insulating film; a second step offorming a bump electrode material contacting to at least a partialregion of the lower electrode and extending upward along an outersidewall of the lower electrode and an outer sidewall of the firstinsulating film; a third step of forming the variable resistor body atan apical part of the bump electrode material; and a fourth step offorming an upper electrode as an electrode to be formed at an upperregion regarding the two electrodes by depositing an electrode materialto layer a second electrode film.

According to the sixth feature regarding the manufacturing method for avariable resistive element according to the present invention, thevariable resistor body is formed at the apical part of the bumpelectrode material extended from the lower electrode in a directiontoward the upper electrode, and then the bump electrode material and theupper electrode are to be connected via the variable resistor body. Thatis to say, it becomes able to manufacture a variable resistive elementwith being reduced an area of electrically contributing region of avariable resistor body.

Moreover, the manufacturing method for a variable resistive elementaccording to the present invention is characterized as a seventh featurein addition to the sixth feature in that the second step comprises thesteps of: forming an electrode film for a bump electrode material bydepositing an electrically conductive material over the whole surfaceincluding a top surface of the first insulating film; and forming thebump electrode material along the outer sidewall of the first electrodefilm and the outer sidewall of the first insulating film by removing theelectrode film for the bump electrode material formed at a region otherthan the outer sidewall of the first electrode film and the outersidewall of the first insulating film.

Further, the manufacturing method for a variable resistive elementaccording to the present invention is characterized as an eighth featurein addition to the sixth or the seventh feature in that the third stepcomprises the steps of: depositing a second insulating film over thewhole surface including the top surface of the first insulating film;and flattening the second insulating film until a top surface of theelectrode film for the bump electrode material is exposed.

Moreover, for achieving the above mentioned object, a manufacturingmethod for a variable resistive element according to a ninth feature ofthe present invention is a manufacturing method for the variableresistive element comprising the third feature construction, andcomprises: a first step of forming a plurality of lower electrodes, eachof which is an electrode to be formed at a lower region regarding thetwo electrodes, by depositing an electrode material onto a substrate tolayer a first electrode film; a second step of depositing a firstinsulating film having an open part, the open part opening for both ofany adjacent pair of the lower electrodes and penetrating the firstinsulating film so as to reach at least a part of each top surface ofthe lower electrodes; a third step of forming a bump electrode materialcontacting to at least a partial region of the lower electrodes andextending upward along an inner sidewall of the open part by depositingan electrically conductive material to layer an electrode film for thebump electrode material and by processing the electrode film for thebump electrode material; a fourth step of filling an inside of the openpart with a second insulating film by depositing the second insulatingfilm and processing the second insulating film; a fifth step of formingthe variable resistor body at an apical part of the bump electrodematerial; and a sixth step of forming an upper electrode as an electrodeto be formed at an upper region regarding the two electrodes bydepositing an electrode material to layer a second electrode film.

Moreover, for achieving the above mentioned object, a manufacturingmethod for a variable resistive element according to a tenth feature ofthe present invention is a manufacturing method for the variableresistive element comprising the third feature construction, andcomprises: a first step of forming a plurality of lower electrodes, eachof which is an electrode to be formed at a lower region regarding thetwo electrodes, by depositing an electrode material onto a substrate tolayer a first electrode film; a second step of depositing a firstinsulating film having a first open part, the first open part openingfor both of any adjacent pair of the lower electrodes and penetratingthe first insulating film so as to reach at least a part of each topsurface of the lower electrodes; a third step of forming a dummy filmcontacting to a partial region of the lower electrodes and extendingupward along an inner sidewall of the first open part by depositing adummy film material and by processing the dummy film material; a fourthstep of filling an inside of the first open part with a secondinsulating film by depositing the second insulating film and byprocessing the second insulating film; a fifth step of forming a secondopen part so that a part of a top surface of the lower electrode isexposed by removing the dummy film; a sixth step of forming the variableresistor body and the bump electrode material at an inside of the secondopen part; and a seventh step of forming an upper electrode as anelectrode to be formed at an upper region regarding the two electrodesby depositing an electrode material to layer a second electrode film,the upper electrode comprising an electrode of bump shape at the insideof the second open part.

According to the ninth or the tenth feature regarding the manufacturingmethod for a variable resistive element according to the presentinvention, the variable resistor body is to be formed at the apical partof the bump electrode material extending as a linear shape from thelower electrode in a direction toward the upper electrode, and then thebump electrode material and the upper electrode are to be connected viathe variable resistor body. That is to say, it becomes able tomanufacture a variable resistive element with being reduced an area ofelectrically contributing region of a variable resistor body.

Moreover, the manufacturing method for a variable resistive elementaccording to the present invention is characterized as an eleventhfeature in addition to the tenth feature in that the dummy film iscomprised of a material different from any materials for the firstinsulating film, the second insulating film and for the first electrodefilm, and the fifth step includes removing only the dummy filmselectively for the first insulating film, the second insulating filmand for the first electrode film, by using an etching method.

Further, the manufacturing method for a variable resistive elementaccording to the present invention is characterized as a twelfth featurein addition to the tenth or the eleventh feature in that the sixth stepincludes forming the variable resistor body by oxidizing a top surfaceof the lower electrode formed at the inside of the second open part.

Moreover, for achieving the above mentioned object, a manufacturingmethod for a variable resistive element according to a thirteenthfeature of the present invention is a manufacturing method for thevariable resistive element comprising the sixth feature construction,and comprises: a first step of forming a plurality of lower electrodes,each of which is an electrode to be formed at a lower region regardingthe two electrodes, by depositing an electrode material onto a substrateto layer a first electrode film; a second step of depositing a firstinsulating film having a first open part, the first open part openingfor both of any adjacent pair of the lower electrodes and penetratingthe first insulating film so as to reach at least a part of each topsurface of the lower electrodes; a third step of forming a first bumpelectrode material contacting to at least a partial region of the lowerelectrodes and extending upward along an inner sidewall of the firstopen part by depositing an electrically conductive material to layer anelectrode film for the first bump electrode material and by processingthe electrode film for the first bump electrode material; a fourth stepof filling an inside of the first open part with a first fillerinsulating film by depositing the first filler insulating film and byprocessing the first filler insulating film; a fifth step of forming thevariable resistor body at an apical part of the first bump electrodematerial; a sixth step of depositing a second insulating film having asecond open part at a region over the first insulating film, the firstfiller insulating film and the variable resistor body, the second openpart penetrating the second insulating film so as to reach at least apart of a top surface of the variable resistor body and extending in asecond direction intersecting the lower electrodes extending in a firstdirection from a top surface view point position; a seventh step offorming a second bump electrode material extending upward along an innersidewall of the second open part by depositing an electricallyconductive material to layer an electrode film for the second bumpelectrode material and by processing the electrode film for the secondbump electrode material; an eighth step of filling an inside of thesecond open part with a second filler insulating film by depositing thesecond filler insulating film and by processing the second fillerinsulating film; and a ninth step of forming an upper electrode as anelectrode to be formed at an upper region regarding the two electrodesby depositing an electrode material to layer a second electrode film andby processing the second electrode film so that the second electrodefilm contacts to a top surface of the second bump electrode material andextends in the second direction.

Moreover, for achieving the above mentioned object, a manufacturingmethod for a variable resistive element according to a fourteenthfeature of the present invention is a manufacturing method for thevariable resistive element comprising the sixth feature construction,and comprises: a first step of forming a plurality of lower electrodes,each of which is an electrode to be formed at a lower region regardingthe two electrodes, by depositing an electrode material onto a substrateto layer a first electrode film; a second step of depositing a firstinsulating film having a first open part, the first open part openingfor both of any adjacent pair of the lower electrodes and penetratingthe first insulating film so as to reach at least a part of each topsurface of the lower electrodes; a third step of forming a first bumpelectrode material contacting to at least a partial region of the lowerelectrodes and extending upward along an inner sidewall of the firstopen part by depositing an electrically conductive material to layer anelectrode film for the first bump electrode material and by processingthe electrode film for the first bump electrode material; a fourth stepof filling an inside of the first open part with a first fillerinsulating film by depositing the first filler insulating film and byprocessing the first filler insulating film; a fifth step of depositinga second insulating film having a second open part at a region over thefirst insulating film, the first filler insulating film and the variableresistor body, the second open part penetrating the second insulatingfilm so as to reach at least a part of a top surface of the variableresistor body and extending in a second direction intersecting the lowerelectrodes extending in a first direction from a top surface view pointposition; a sixth step of forming the variable resistor body at anapical part of the first bump electrode material formed at an inside ofthe second open part; a seventh step of forming the second bumpelectrode material extending upward along an inner sidewall of thesecond open part by depositing an electrically conductive material tolayer an electrode film for the second bump electrode material and byprocessing the electrode film for the second bump electrode material; aeighth step of filling an inside of the second open part with a secondfiller insulating film by depositing the second filler insulating filmand by processing the second filler insulating film; and a ninth step offorming an upper electrode as an electrode to be formed at an upperregion regarding the two electrodes by depositing an electrode materialto layer a second electrode film and by processing the second electrodefilm so that the second electrode film contacts to a top surface of thesecond bump electrode material and extends in the second direction.

According to the thirteenth or the fourteenth feature regarding themanufacturing method for a variable resistive element according to thepresent invention, the first bump electrode material extending as alinear shape from the lower electrode in a direction toward the upperelectrode and the second bump electrode material extending as a linearshape from the upper electrode in a direction toward the lower electrodeare to be electrically connected via the variable resistor body. That isto say, it becomes able to manufacture a variable resistive element withbeing reduced an area of electrically contributing region of a variableresistor body.

Moreover, for achieving the above mentioned object, a manufacturingmethod for a variable resistive element according to a fifteenth featureof the present invention is a manufacturing method for the variableresistive element comprising the eighth feature construction, andcomprises: a first step of layering an electrode film for a bumpelectrode material by depositing the base insulating film on a substrateand depositing an electrically conductive material onto the baseinsulating film; a second step of forming a lower electrode as theelectrode to be formed at a lower region regarding the two electrodes bydepositing an electrode material onto the electrode film for the bumpelectrode material to layer a first electrode film, by depositing afirst insulating film onto the first electrode film, and by processingthe first electrode film and the first insulating film; a third step offorming a sidewall film along an outer sidewall of the lower electrodeand an outer sidewall of the first insulating film by depositing asecond insulating film and by processing the second insulating film; afourth step of forming the bump electrode material contacting to atleast a partial region of the lower electrode and extending along a topsurface of the base insulating film; a fifth step of forming thevariable resistor body at an apical part of the bump electrode material;and a sixth step of forming an upper electrode as an electrode to beformed at an upper region regarding the two electrodes by depositing anelectrode material to layer a second electrode film.

According to the fifteenth feature regarding the manufacturing methodfor a variable resistive element according to the present invention, thevariable resistor body is to be formed at the apical part of the bumpelectrode material extending from either one of the electrodes in adirection toward another one of the electrodes as a linear shape on thebase insulating film, and then the bump electrode material and the otherone of the electrodes are to be connected via the variable resistorbody. That is to say, it becomes able to manufacture a variableresistive element with being reduced an area of electricallycontributing region of a variable resistor body.

Moreover, the manufacturing method for a variable resistive elementaccording to the present invention is characterized as a sixteenthfeature in addition to the fifteenth feature in that the fourth stepincludes forming the bump electrode material by removing the electrodefilm for the bump electrode material formed at a region other thanregions under the lower electrode and the sidewall film.

Moreover, for achieving the above mentioned object, a manufacturingmethod for a variable resistive element according to a seventeenthfeature of the present invention is a manufacturing method for thevariable resistive element comprising the eighth feature construction,and comprises a first step of layering an electrode film for a bumpelectrode material by depositing the base insulating film on a substrateand depositing an electrically conductive material onto the baseinsulating film; a second step of forming the bump electrode materialextending along a top surface of the base insulating film by depositinga dummy film onto the electrode film for the bump electrode material andby processing the electrode film for the bump electrode material and thedummy film; a third step of forming the variable resistor body at anapical part of the bump electrode material; a fourth step of forming alower electrode as the electrode to be formed at a lower regionregarding the two electrodes by depositing an electrode material tolayer a first electrode film, the lower electrode contacting to the bumpelectrode material; a fifth step of forming an open part to expose a topsurface of the bump electrode material by depositing a first insulatingfilm onto the lower electrode, by processing the first insulating film,and by removing the dummy film; a sixth step of depositing a secondinsulating film for a region including at least a sidewall of the lowerelectrode; and a seventh step of forming an upper electrode as theelectrode to be formed at an upper region regarding the two electrodesby depositing an electrode material to layer a second electrode film inan outer region of the second insulating film, on the first insulatingfilm and on the bump electrode material.

According to the seventeenth feature regarding the manufacturing methodfor a variable resistive element according to the present invention, thevariable resistor body is to be formed at the apical part of the bumpelectrode material extending from either one of the electrodes in adirection toward another one of the electrodes as a linear shape on thebase insulating film, and then the bump electrode material and the otherone of the electrodes are to be connected via the variable resistorbody. That is to say, it becomes able to manufacture a variableresistive element with being reduced an area of electricallycontributing region of a variable resistor body.

Moreover, the manufacturing method for a variable resistive elementaccording to the present invention is characterized as an eighteenthfeature in addition to the seventeenth feature in that the dummy film isformed of a material different from any materials for the firstinsulating film, the electrode film for the bump electrode material andfor the first electrode film, and the fifth step includes removing onlythe dummy film selectively for the first insulating film, the electrodefilm for the bump electrode material and for the first electrode film,by using an etching method.

Further, a manufacturing method for a variable resistive elementaccording to a nineteenth feature of the present invention in additionto any one of the features from the first through the third, from thesixth through the tenth, and from the fifteenth through the eighteenthfurther comprises a step of forming the variable resistor body byforming the bump electrode material and depositing a variable resistorbody material onto at least the bump electrode material to layer avariable resistor body film.

Here, it may also available to layer the variable resistor body film bydepositing the variable resistor body material using either one of aspattering method or a CVD method.

Moreover, a manufacturing method for a variable resistive elementaccording to a twentieth feature of the present invention in addition toany one of the features from the first through the eleventh and from thethirteenth through the eighteenth further comprises a step of formingthe variable resistor body by forming the bump electrode material andoxidizing an exposed part of the bump electrode material.

According to the twentieth feature regarding the manufacturing methodfor a variable resistive element according to the present invention, itis able to realize a variable resistive element by using an extremelysimple process, because the variable resistor body is to be formed byoxidizing the exposed part of the bump electrode material. Here, it isavailable to use such as a (high temperature) thermal oxidation method,an oxygen plasma oxidation method, an ozone oxidation method, or thelike, as an oxidation method therefor.

Moreover, the manufacturing method for a variable resistive elementaccording to the present invention is characterized as a twenty-firstfeature in addition to any one of the features from the first throughthe twentieth in that the bump electrode material is a titanium nitride.

According to the twenty-first feature construction regarding thevariable resistive element according to the present invention, itbecomes easy for designing processes because it is available to use atitanium based material for the bump electrode material, which has beenconventionally used in general purpose in semiconductor processes.

Moreover, the manufacturing method for a variable resistive elementaccording to the present invention is characterized as a twenty-secondfeature in addition to any one of the features from the first throughthe twenty-first in that the variable resistor body is a titanium oxideor a titanium oxynitride.

Effects of the Invention

According to the variable resistive element of the present invention, anarea of an electrically contributing region of a variable resistor bodyis not to be constrained by a formative area specified by manufacturingprocesses, because a shape of a contact surface of between the variableresistor body and either one of electrodes or the other one of theelectrodes is an annular or a plurally-separated linear shape. Hence, itbecomes able to obtain the area of the electrically contributing regionof the variable resistor body smaller than the formative area specifiedby the manufacturing processes. Therefore, it becomes able to reduce thecurrent consumption at a period of programming or erasing thereby, andthen it becomes able to manufacture a memory element reproducibly with astable switching operation without occurring a programming impossibledue to a low electrical resistance thereof. Moreover, according to themanufacturing method for a variable resistive element regarding thepresent invention, it becomes able to manufacture such as the abovementioned variable resistive element which is able to obtain the area ofthe electrically contributing region of the variable resistor bodysmaller than the formative area specified by the manufacturingprocesses.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a brief cross sectional view showing a configuration of avariable resistive element according to the first embodiment of thepresent invention.

FIG. 2 is a plane pattern diagram showing a memory cell array of an 1Rconfiguration.

FIG. 3 is a brief cross sectional view showing a variable resistiveelement according to the first embodiment of the present invention inorder of manufacturing process.

FIG. 4 is a brief cross sectional view showing the variable resistiveelement according to the first embodiment of the present invention inorder of manufacturing process.

FIG. 5 is a plane pattern diagram showing electrically contributingregions in variable resistor bodies according to a conventionalconfiguration and the first embodiment of the present invention,respectively.

FIG. 6 is a brief cross sectional view showing a configuration of avariable resistive element according to the second embodiment of thepresent invention.

FIG. 7 is a brief cross sectional view showing a variable resistiveelement according to the second embodiment of the present invention inorder of manufacturing process.

FIG. 8 is a brief cross sectional view showing the variable resistiveelement according to the second embodiment of the present invention inorder of manufacturing process.

FIG. 9 is a brief cross sectional view showing the enlarged crosssectional views along the X-X′ dashed line for FIG. 7C, FIG. 7D and FIG.8E.

FIG. 10 is a brief cross sectional view showing a variable resistiveelement according to the third embodiment of the present invention inorder of manufacturing process.

FIG. 11 is a brief cross sectional view showing the variable resistiveelement according to the third embodiment of the present invention inorder of manufacturing process.

FIG. 12 is a brief cross sectional view showing a configuration of avariable resistive element according to the fourth embodiment of thepresent invention.

FIG. 13 is a brief cross sectional view showing a variable resistiveelement according to the fourth embodiment of the present invention inorder of manufacturing process.

FIG. 14 is a brief cross sectional view showing the variable resistiveelement according to the fourth embodiment of the present invention inorder of manufacturing process.

FIG. 15 is a plane pattern diagram showing an electrically contributingregion of a variable resistor body according to a conventionalconfiguration and the fourth embodiment of the present invention.

FIG. 16 is a brief cross sectional view showing a variable resistiveelement according to the fifth embodiment of the present invention inorder of manufacturing process.

FIG. 17 is a plane pattern diagram comparing between a variableresistive element of a conventional configuration and a variableresistive element according to the fifth embodiment.

FIG. 18 is a brief cross sectional view showing a variable resistiveelement according to the sixth embodiment of the present invention inorder of manufacturing process.

FIG. 19 is a brief cross sectional view showing a configuration of avariable resistive element according to the seventh embodiment of thepresent invention.

FIG. 20 is a brief cross sectional view showing a variable resistiveelement according to the seventh embodiment of the present invention inorder of manufacturing process.

FIG. 21 is a brief cross sectional view showing the variable resistiveelement according to the seventh embodiment of the present invention inorder of manufacturing process.

FIG. 22 is a brief cross sectional view showing the variable resistiveelement according to the seventh embodiment of the present invention inorder of manufacturing process.

FIG. 23 is a plane pattern diagram showing a pattern layout of openparts regarding manufacturing processes of a variable resistive elementaccording to the seventh embodiment of the present invention.

FIG. 24 is a plane pattern diagram showing an electrically contributingregion of a variable resistor body according to a conventionalconfiguration and the seventh embodiment of the present invention.

FIG. 25 is a brief cross sectional view showing a configuration of avariable resistive element according to the eighth embodiment of thepresent invention.

FIG. 26 is a brief cross sectional view showing a variable resistiveelement according to the eighth embodiment of the present invention inorder of manufacturing process.

FIG. 27 is a brief cross sectional view showing the variable resistiveelement according to the eighth embodiment of the present invention inorder of manufacturing process.

FIG. 28 is a brief cross sectional view showing a configuration of avariable resistive element according to the ninth embodiment of thepresent invention.

FIG. 29 is a brief cross sectional view showing a variable resistiveelement according to the ninth embodiment of the present invention inorder of manufacturing process.

FIG. 30 is a brief cross sectional view showing the variable resistiveelement according to the ninth embodiment of the present invention inorder of manufacturing process.

FIG. 31 is a plane pattern diagram showing a pattern layout of openparts regarding manufacturing processes of a variable resistive elementaccording to the ninth embodiment of the present invention.

FIG. 32 is a plane pattern diagram showing an electrically contributingregion of a variable resistor body according to a conventionalconfiguration and the ninth embodiment of the present invention.

FIG. 33 is a brief cross sectional view showing a variable resistiveelement according to a modified example regarding the ninth embodimentof the present invention in order of manufacturing process.

FIG. 34 is a brief cross sectional view showing a configuration of avariable resistive element according to the tenth embodiment of thepresent invention.

FIG. 35 is a brief cross sectional view showing a variable resistiveelement according to the tenth embodiment of the present invention inorder of manufacturing process.

FIG. 36 is a brief cross sectional view showing the variable resistiveelement according to the tenth embodiment of the present invention inorder of manufacturing process.

FIG. 37 is a plane pattern diagram showing an electrically contributingregion of a variable resistor body according to a conventionalconfiguration and the tenth embodiment of the present invention.

FIG. 38 is a brief cross sectional view showing a configuration of avariable resistive element according to the eleventh embodiment of thepresent invention.

FIG. 39 is a brief cross sectional view showing a variable resistiveelement according to the eleventh embodiment of the present invention inorder of manufacturing process.

FIG. 40 is a brief cross sectional view showing the variable resistiveelement according to the eleventh embodiment of the present invention inorder of manufacturing process.

FIG. 41 is a plane pattern diagram showing a layout of a BE patternregarding manufacturing processes of a variable resistive elementaccording to the eleventh embodiment of the present invention.

FIG. 42 is a diagrammatic perspective view showing a basic structure ofa conventional variable resistive element.

FIG. 43 is a circuit diagram schematically showing one configurationexample of a memory cell array using memory cells of 1T/1R typecomprising one selective transistor and one variable resistive element.

FIG. 44 is a cross sectional pattern diagram showing one configurationexample of a conventional memory cell structure of 1T/1R type.

FIG. 45 is a circuit diagram schematically showing one configurationexample of a memory cell array using memory cells of 1R type comprisingone variable resistive element.

FIG. 46 is a diagrammatic perspective view schematically showing oneconfiguration example of a conventional memory cell structure of 1Rtype.

EXPLANATION OF REFERENCES

-   R: Variable Resistive Element-   T: Selective Transistor-   TE, 4, 14, 24, 34, 44, 54, 64, 95, 122, 124, 126, 130, 132, 136,    138, 201, 220, 243, 304, 314, 334, 344, 404, 414, 428, 434, 444,    454, 464: Upper Electrode-   BE, 1, 11, 21, 31, 41, 51, 61, 89, 111, 121, 123, 125, 129, 131,    135, 137, 203, 218, 241, 301, 311, 331, 341, 401, 411, 431, 441,    451, 461: Lower Electrode-   2, 22, 32, 42, 52, 62, 92, 108, 302, 312, 332, 342, 426, 432, 442,    452, 462: Bump Electrode Material-   133, 402, 412: First Bump Electrode Material-   134, 406, 420: Second Bump Electrode Material-   3, 23, 33, 43, 53, 63, 94, 110, 202, 219, 242, 303, 313, 333, 343,    403, 413, 425,-   433, 443, 453, 463: Variable Resistor Body-   A, 91, 128, 319, 349, 352, 419, 424: Open Part-   468: Stepped Part-   5, 25, 55, 244, 305, 405, 435, 455: Base Substrate-   16, 36, 46, 66, 81, 101, 211, 316, 346, 416, 446, 466: Semiconductor    Substrate-   15, 35, 45, 65, 87, 107, 315, 345, 415, 445, 465: Base Insulating    Film-   17, 37, 47, 67: SiN Film-   18, 19, 20, 38, 39, 40, 48, 49, 50, 68, 69, 90, 93, 96, 109, 112,    317, 320, 321, 347, 350, 353, 417, 421, 422, 427, 429, 447, 448,    449, 469, 470, 471: SiO₂ Film-   318, 351, 467: SiN Film-   348, 418, 423: Al₂O₃ Film-   WBE, WTE: Open Part Pattern-   RBE: Wiring Pattern-   82, 102, 212: Element Isolation Region-   83, 103, 213: Gate Insulating Film-   84, 104, 214: Gate Electrode-   85, 105, 215: Drain Region-   86, 106, 216: Source Region-   88, 97, 98, 113, 114, 217, 221, 222: Contact Plug-   99, 115, 223: Bit Wiring-   100, 116, 224: Source Wiring-   127: Open Part or Electrode Size-   S1, S2, S3, S4, S5, S6, S7, S8, S9: Electrically Contributing Region    in the variable resistor body-   204, 231: Memory Cell Array-   205, 232: Bit Line Decoder-   206, 233: Word Line Decoder-   207: Source Line Decoder-   BL1, BL2, . . . , BLm: Bit Line-   WL1, WL2, . . . , WLn: Word Line-   SL1, SL2, . . . , SLn: Source Line

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments will be described in detail below with referenceto the drawings regarding a variable resistive element (properlyreferred to as the present invention element hereinafter) and itsmanufacturing method (properly referred to as the present inventionmethod hereinafter) according to the present invention.

The present invention element comprises a configuration that aconnection is performed between an upper electrode and a lower electrodevia a variable resistor body, wherein the configuration is that a bumpelectrode material is provided to be electrically connected to eitherone of the electrodes, in order to make a contact area between eitherone of the electrodes and the variable resistor body be narrower thanthat of the conventional configuration. The following description is tobe focused in particular regarding manufacturing processes of such thebump electrode material.

The First Embodiment

The first embodiment according to the present invention element and thepresent invention method (properly referred to as the present embodimenthereinafter) will be described in detail below with reference to FIG. 1to FIG. 5.

FIG. 1 is a brief cross sectional view showing the present inventionelement according to the present embodiment. The present inventionelement according to the present embodiment comprises a configurationthat a lower electrode wiring 1 and an upper electrode wiring 4 areformed on a base substrate 5, and a variable resistor body 3 as a memorymaterial body is formed between the upper and the lower electrodewirings, wherein a bump electrode material 2 comprised of any ofelectrically conductive materials is electrically connected to the lowerelectrode wiring 1, and the variable resistor body 3 is formed on anapical part of the bump electrode material 2, as shown in FIG. 1.

The following is a description as an example for the case of applyingthe present invention element comprised of such the configuration to amemory cell of 1R type. FIG. 2 is a plane pattern diagram showing amemory cell array of an 1R configuration. Moreover, FIG. 3 and FIG. 4are views showing manufacturing processes for the present inventionelement according to the present embodiment, as shown by FIG. 3A to FIG.4G in order of each manufacturing process (Those are separated into twoviews for convenience' sake due to page space). In FIG. 3 and FIG. 4, across sectional pattern diagram along an X-X′ dashed line in FIG. 2,that is to say, along the upper electrode wiring TE, and the crosssectional pattern diagram along an Y-Y′ dashed line therein, that is tosay, along the lower electrode wiring BE are shown at the left side andthe right side respectively therein.

Manufacturing processes for the present invention element according tothe present embodiment will be described in detail below with referenceto FIG. 3 and FIG. 4.

First, a base insulating film 15 is to be formed on a semiconductorsubstrate 16 where peripheral circuits and the like (not shown) areproperly formed on. According to the present embodiment, afterdepositing the base insulating film 15 of borophosphosilicate glass(BPSG) with a thickness of 1500 nm, a surface of such the film isflattened by polishing the surface of the BPSG film 15 on a top surfaceof the semiconductor substrate 16 to be the thickness of 800 nm using aso-called chemical mechanical polishing (CMP) method. Next, a materialfilm (a first electrode film) 11 to be a lower electrode wiring is to bedeposited thereon. According to the present embodiment, a Ti film of 5nm thickness, a TiN film of 20 nm thickness, an Al—Cu film of 200 nmthickness, another Ti film of 5 nm thickness, and another TiN film of100 nm thickness are to be deposited in order using a spattering methodrespectively, as a multilayer structure of TiN/Ti/Al—Cu/TiN/Ti.Moreover, an SiN film (a second insulating film) 17 is to be depositedwith the thickness of 150 nm on the material film 11 to be the lowerelectrode wiring using a chemical vapor deposition (CVD) method. Next,the lower electrode wiring is to be formed by etching the SiN film 17and the material film 11 to be the lower electrode wiring using aphotolithography method with a resist as a mask (not shown) patterned asa line and space (L/S) shape shown as the lower electrode wiring BE inFIG. 2. And then as shown in FIG. 3A, an SiO₂ film (a first insulatingfilm) 18 is to be deposited with the thickness of 600 nm using the CVDmethod thereunto.

Next, the SiO₂ film 18 is to be flattened and a top surface of the SiNfilm 17 is to be exposed by polishing the SiO₂ film 18 to the topsurface level of the SiN film 17 using the CMP method, as shown in FIG.3B. Here, the flattening method is not limited to the CMP method, as itmay be also available to use any proper flattening technology includingsuch as a spin-on method, the spin-on method combined with an etch backmethod, or the like.

Next, an open part A is to be formed by removing the SiN film 17selectively for the SiO₂ film 18 and for the material film 11 to be thelower electrode wiring, using a dry etching method with an NF₃ plasma ofdownstream type, as shown in FIG. 3C. Here, the removing method for theSiN film 17 is not limited to the dry etching method, as it may beremoved using a wet etching method with a heated phosphor treatment aswell.

Next, a TiN film (an electrode film for a bump electrode material) 12 asone example of the material film to be a bump electrode material is tobe deposited with the thickness of 40 nm using the spattering methodover the surface thereof, as shown in FIG. 3D. In this case, it is ableto form the TiN film 12 along an inner sidewall in the open part A withthe thickness of 20 nm for example. Moreover, an SiO₂ film (a thirdinsulating film) 19 is to be deposited over the surface with thethickness of 600 nm using the CVD method thereafter. Here, the TiN film12 is formed along the open part A, so that the inside of the open partA may be not to be filled therewith.

Next, the SiO₂ film 19 is to be flattened and a top surface of the TiNfilm 12 is to be exposed by polishing the SiO₂ film 19 using the CMPmethod to the top surface level of the TiN film 12. And then the bumpelectrode material 12 is to be formed by removing the TiN film 12 on theSiO₂ film 18 except that inside the open part A using the etch backmethod thereafter, as shown in FIG. 4E.

Next, a TiO₂ film 13 is to be formed by thermal oxidation in anatmosphere including oxygen at a temperature of between 250 and 450° C.as one example of the variable resistor body formed by oxidizing anexposed apical part of the bump electrode material 12 comprised of theTiN film, as shown in FIG. 4F. According to the present embodiment, thevariable resistor body is to be the TiO₂ film, however, it is alsopossible to form a TiO_(2-x)N_(x) film having a characteristic ofvariable electrical resistance by controlling properly an oxidationcondition, such as an oxidation temperature, an oxygen concentration, orthe like.

Next, a material film (a second electrode film) 14 to be an upperelectrode wiring is to be formed over the surface thereof. According tothe present embodiment, a TiN film of 20 nm thickness, an Al—Cu film of200 nm thickness, a Ti film of 5 nm thickness, and another TiN film of100 nm thickness are to be deposited in order using the spatteringmethod respectively, as a multilayer structure of TiN/Ti/Al—Cu/TiN.Next, the upper electrode wiring 14 is to be formed by etching thematerial film 14 to be the upper electrode wiring, with the resist asthe mask (not shown) patterned as the line and space (L/S) shape shownas the upper electrode wiring TE in FIG. 2, using the photolithographymethod. Moreover, an interlayer insulating film 20 is to be depositedthereunto, and then a contact wiring (not shown) and a metal wiring (notshown) are to be formed for the upper electrode wiring 14 and the lowerelectrode wiring 11 respectively, as shown in FIG. 4G.

Regarding such the variable resistive element formed thereby, it becomesable to reduce an area of a contact surface between the variableresistor body and any of the electrodes comparing to that of theconventional configurations. The following is a detailed description inthis regard with reference to the drawings.

FIG. 5 is a plane pattern diagram of the variable resistive elementaccording to the present embodiment comparing to a variable resistiveelement of a conventional configuration. FIG. 5A shows the one of theconventional configuration, and FIG. 5B shows regarding theconfiguration according to the present embodiment.

Regarding the conventional memory cell of 1R type, a cross point regionas a region S1 (a shaded area in the figure) at an intersection of anlower electrode wiring 121 and an upper electrode wiring 122 is theelectrically contributing region in the variable resistor body, as shownin FIG. 5A.

On the contrary, according to the variable resistive element regardingthe present embodiment, there is provided the configuration that thebump electrode material is to be formed only in a partial region at aninterface side on a lower electrode wiring 123 and to be electricallyconnected to an upper electrode wiring. And then the cross point regionas a region S2 (a shaded area in the figure) at the intersection of suchthe bump electrode material and the upper electrode wiring 124 is to bethe electrically contributing region in the variable resistor body.

The region S2 has a band shape with a width of at least the filmthickness of the bump electrode material, and it is able to reduce thearea comparing to the region S1 regarding the conventional variableresistive element. Moreover, it is able to form the bump electrodematerial using a self-aligned process, and then it is able to changearbitrarily such the area by controlling the film thickness thereof.

That is to say, it is able to reduce a contact area according to theconfiguration regarding the present embodiment comparing to the contactarea of the conventional configuration. Thus, it becomes able to reducea current consumption, and it becomes possible to manufacture a memoryelement reproducibly with a stable switching operation without becominga programming impossible, by configuring a nonvolatile memory deviceusing such the variable resistive element.

Here, the deposited insulating films are to be the SiO₂ film 18 and theSiO₂ film 19 in the above description, however, the insulating film isnot limited to such the SiO₂ film; it may be also available to use anyof proper insulating films including such as an SiN film, a polyimidefilm, an SiOF film, or the like. Moreover, regarding the deposition ofthe insulating films, it may be deposited using any proper depositiontechnology including such as a pulsed laser deposition, anrf-spattering, an electron beam evaporation, a thermal evaporation, anorgano-metal deposition, a spin-on deposition, a metalorganic chemicalvapor deposition, or the like. Ditto regarding each of the followingembodiments.

The Second Embodiment

The second embodiment according to the present invention element and thepresent invention method (properly referred to as the present embodimenthereinafter) will be described in detail below with reference to FIG. 6to FIG. 9. Here, a detailed description for a process which duplicatesthat of the first embodiment is properly omitted with mentioning thateffect.

Moreover, the description as a first insulating film or a secondinsulating film is named for an insulating film for convenience' sake inorder of depositing thereof for each of the embodiments, and it is to beused independently for each of the embodiment except a case ofmentioning in particular. Ditto regarding each of the followingembodiments.

FIG. 6 is a cross sectional pattern diagram showing the presentinvention element according to the present embodiment. The presentinvention element according to the present embodiment comprises aconfiguration that a lower electrode wiring 31 and an upper electrodewiring 34 are formed on a base substrate 35, and a variable resistorbody 33 as a memory material body is formed between the upper and thelower electrodes, wherein a bump electrode material 32 comprised of anelectrically conductive material is connected to the upper electrode 34,and the bump electrode material 32 is connected to the lower electrode31 via the variable resistor body 33, as shown in FIG. 6.

Next, the manufacturing method for a variable resistive elementaccording to the present embodiment will be described in detail below,as an example for the case of applying to a memory cell of 1R type. FIG.7 and FIG. 8 are views showing manufacturing processes for the presentinvention element according to the present embodiment, as shown by FIG.7A to FIG. 8G in order of each manufacturing process (Those areseparated into two views for convenience' sake due to page space). InFIG. 7 and FIG. 8, a cross sectional pattern diagram along the X-X′dashed line, that is to say, along the upper electrode wiring TE in FIG.2 for showing the memory cell array of the 1R configuration, and a crosssectional pattern diagram along the Y-Y′ dashed line therein, that is tosay, along the lower electrode wiring BE are shown at the left side andthe right side respectively therein. Moreover, FIG. 9 is a view showingthe enlarged pattern diagram as shown in FIG. 7 or FIG. 8 for describingone process in the manufacturing processes.

Manufacturing processes for the present invention element according tothe present embodiment will be described in detail below with referenceto FIG. 7 to FIG. 9.

First, by performing the processes as completely similar to that of thefirst embodiment as shown in FIG. 3A, a material film (a first electrodefilm) 31 to be a lower electrode wiring processed using a pattern oflower electrode wiring BE and an SiN film (a second insulating film) 37are to be formed onto a base insulating film 35 on a semiconductorsubstrate 36, as shown in FIG. 7A. Moreover, an SiO₂ film (a firstinsulating film) 38 is to be deposited over the surface thereof.

Next, an open part A is to be formed on the lower electrode wiring 31 asshown in FIG. 7B, by performing the processes as completely similar tothat of the first embodiment as shown in FIG. 3B and FIG. 3C.

Next, a TiN film (an electrode film for a bump electrode material) 32 isto be deposited over the surface thereof as one example for a materialfilm to be a bump electrode material, as shown in FIG. 7C. The followingis a description regarding a deposition method therefor, with referenceto an enlarged view. FIG. 9A is a view showing by enlarging the crosssectional view along the X-X′ dashed line as shown in FIG. 7C.

As shown in FIG. 9A, the TiN film 32 is deposited using the spatteringmethod so that the TiN film 32 at an open part A becomes an overhangshape. For example, in a case of assuming a thickness of the TiN film 32at a flat part on the insulating film 38 as 40 nm, the thickness of suchthe TiN film deposited at an inner sidewall of the open part A is to bebetween 3 nm and 20 nm, and then the film thickness thereof becomes tobe thinner toward a bottom of the open part. It is able to form easilyin such the shape by controlling spattering conditions properly, such asa pressure, a substrate bias, a presence of a collimator, or the like.

Next, a process using an etch back is to be performed until the TiN film32 on the insulating film 38 is completely removed, as shown in FIG. 7D.The TiN film 32 is to be retained only at the sidewall of the open partA by such the process, as shown with enlarging in FIG. 9B.

Next, an SiO₂ film (a third insulating film) 39 is to be deposited overthe surface with a deposition thickness of 600 nm using a CVD method, asshown in FIG. 8E. Due to an oxidative atmosphere for a process to formsuch the SiO₂ film 39, a part of the retained TiN film 32 at the innersidewall of the open part A cannot help but be oxidized at the period ofdepositing the SiO₂ film 39. According to the configuration of thepresent embodiment, the retained film thickness of the TiN film 32 isthinner toward the bottom of the open part A, as shown in FIG. 9B.Hence, a TiO₂ film is to be formed as the TiN film 32 located in thevicinity of the bottom of the open part A is oxidized in the process offorming the SiO₂ film 39. And then such the formed TiO₂ film is to beused as a material film for a variable resistor body. That is to say, aTiO₂ film 33 as a variable resistor body is to be formed at an interfacepart between the TiN film 32 and the lower electrode 31 (refer to FIG.9C). Thus, there becomes provided a configuration in that a bumpelectrode material 32 and the lower electrode 31 are to be connected viathe TiO₂ film 33.

Next, a surface of the SiO₂ film 39 is to be flattened and the TiN film32 is to be exposed by polishing the SiO₂ film 39 using the CMP methodto a top surface level of the TiN film 32, as shown in FIG. 8F. And thenan upper electrode 34 is to be formed by patterning a material film (asecond electrode film) to be the upper electrode wiring 34 and the bumpelectrode material 32 at a lower part thereof at the same time. This isto be an object for preventing an adjacent pair of the upper electrodesfrom shorting out due to the bump electrode material 32, because each ofextending directions for the upper electrode wiring 34 and the bumpelectrode material 32 crosses each other.

Moreover, an interlayer insulating film 40 is to be deposited thereafter(refer to FIG. 8G), and then a contact wiring (not shown) and a metalwiring (not shown) are to be formed for the upper electrode wiring 34and the lower electrode wiring 31 respectively.

According to the configuration of the present embodiment, the upperelectrode wiring 34 and the TiN film 32 retained at the inside of theopen part A are electrically connected. That is to say, the bumpelectrode material 32 is connected to the upper electrode 34 as shown inFIG. 6, and it comprises the variable resistor body 33 at an edge partin a downward direction therefrom. Therefore, the plane pattern diagramaccording to the present embodiment becomes to be similar to that of thefirst embodiment as shown in FIG. 5B, showing the configuration in thatthe bump electrode material is to be formed only in a partial region atan interface side of the region on a lower electrode wiring 123 and tobe electrically connected to an upper electrode wiring, and then aregion S2 (a shaded area in the figure) as a cross point region betweensuch the bump electrode material and the upper electrode wiring 124becomes to be an electrically contributing region of the variableresistor body.

According to such the variable resistive element formed thereby, it isable to reduce an area of a contact surface between the variableresistor body and any of the electrodes compared with that of theconventional configuration, as similar to that according to the firstembodiment. Thus, it becomes able to reduce a current consumption, andit becomes possible to manufacture a memory element reproducibly with astable switching operation without occurring a programming impossible,by configuring a nonvolatile memory device using such the element.

Here, according to the present embodiment, the oxidation to beprogressed at the period of depositing the oxide film is used, however,it is not limited thereto, and it may be also available to use anotheroxidation method therefor, such as a thermal oxidation in an oxygenatmosphere, an oxidation in an oxygen plasma, an ozone oxidation, or thelike.

The Third Embodiment

The third embodiment according to the present invention element and thepresent invention method (properly referred to as the present embodimenthereinafter) will be described in detail below with reference to FIG. 10and FIG. 11. Here, a detailed description for a process which duplicatesthat of the first embodiment is properly omitted with mentioning thateffect.

According to the above mentioned first and the second embodiment, thevariable resistor body is formed by oxidizing the bump electrodematerial, however, the present invention element is to be formed using amethod for depositing a variable resistor body directly onto a bumpelectrode material according to the present embodiment. The following isa description as an example for the case of applying the manufacturingmethod for a variable resistive element according to the presentembodiment to a memory cell of 1R type.

FIG. 10 and FIG. 11 are views showing manufacturing processes for thepresent invention element according to the present embodiment, as shownby FIG. 10A to FIG. 11G in order of each manufacturing process (Thoseare separated into two views for convenience' sake due to page space).In FIG. 10 and FIG. 11, a cross sectional pattern diagram along the X-X′dashed line, that is to say, along the upper electrode wiring TE in FIG.2 for showing the memory cell array of the 1R configuration, and a crosssectional pattern diagram along the Y-Y′ dashed line, that is to say,along the lower electrode wiring BE in FIG. 2 are shown at the left sideand the right side respectively therein.

First, by performing the processes as completely similar to that of thefirst embodiment as shown in FIG. 3A, a material film (a first electrodefilm) 41 to be a lower electrode wiring processed using a pattern oflower electrode wiring BE and an SiN film (a second insulating film) 47are to be formed onto a base insulating film 45 on a semiconductorsubstrate 46, as shown in FIG. 10A. Moreover, an SiO₂ film (a firstinsulating film) 48 is to be deposited over the surface thereof.

Next, the SiO₂ film 48 is to be flattened until a surface of the SiNfilm 47 becomes exposed as shown in FIG. 10B, by performing theprocesses as completely similar to that of the first embodiment as shownin FIG. 3B.

Next, an open part A is to be formed on the lower electrode wiring 41 asshown in FIG. 10C, by performing the processes as completely similar tothat of the first embodiment as shown in FIG. 3C.

Next, a TiN film 42 as one example for a bump electrode material (anelectrode film for the bump electrode material) and then an SiO₂ film 49are to be deposited over the surface thereof, as shown in FIG. 10D, byperforming the processes as completely similar to that of the firstembodiment as shown in FIG. 3D.

Next, the bump electrode material 42 comprised of the TiN film is to beformed as shown in FIG. 11E, by performing the processes as completelysimilar to that of the first embodiment as shown in FIG. 3E.

Next, a TiO₂ film 43 as one example of a material film for a variableresistor body (a variable resistor body film) 43 is to be deposited overthe surface thereof, as shown in FIG. 11F. It is able to deposit theTiO₂ film 43 by applying a direct current (DC) power of 1.5 kW/cm² to aTi target using a magnetron spattering method under the conditions of agas flow rate of Ar/O₂=5 sccm/15 sccm and a pressure of between 3 and 15mTorr, as one example of a deposition method therefor.

Next by performing the processes as completely similar to that of thefirst embodiment as shown in FIG. 3G, an upper electrode wiring 44 andan interlayer insulating film 50 are formed, and then a contact wiring(not shown) and a metal wiring (not shown) for the upper electrodewiring 44 and for the lower electrode wiring 41 are to be formedrespectively.

According to the configuration of the present embodiment, there becomesprovided a configuration in that the upper electrode wiring 44 and thebump electrode material 42 are to be connected via the variable resistorbody 43, and the bump electrode material 42 is to be connected to thelower electrode 41. Therefore, the plane pattern diagram according tothe present embodiment becomes to be similar to that of the first andthe second embodiments as shown in FIG. 5B, showing the configuration inthat the bump electrode material is to be formed only in a partialregion at an interface side of the region on a lower electrode wiring123 and to be electrically connected to an upper electrode wiring, andthen a region S2 (a shaded area in the figure) at a cross point regionbetween such the bump electrode material and the upper electrode wiring124 becomes to be an electrically contributing region of the variableresistor body.

According to such the variable resistive element formed thereby, it isable to reduce an area of a contact surface between the variableresistor body and any of the electrodes compared with that of theconventional configuration, as similar to that according to the firstand the second embodiments. Thus, it becomes able to reduce a currentconsumption, and it becomes possible to manufacture a memory elementreproducibly with a stable switching operation without occurring aprogramming impossible, by configuring a nonvolatile memory device usingsuch the element.

Here, the variable resistor body 43 is to be the titanium oxide formedusing the spattering method according to the above description, however,the deposition method is not limited thereto, and it may be formed usingthe CVD method as well. In the case of forming thereof using the CVDmethod, it may be formed with using a material of such as TiCl₄, or anorgano-metal of such as Ti(OCH₃)₄, Ti(OC₂H₆)₄, Ti(O-i-C₃H₇)₄,Ti(O-n-C₄H₇)₄, Ti(O-n-C₄H₉)₄, Ti(O-sec-C₄H₉)₄, Ti(N(CH₃)₂)₄,Ti(N(C₂H₅)₂)₄, or the like, by introducing into a reaction chamber usinga carburetor for reacting with oxygen with a substrate heated at atemperature of between 250° C. and 500° C.

Moreover, not only the titanium oxide but also a titanium oxynitridefilm may be also applicable to the variable resistor body 43. Forexample, it is also possible to use a TiO_(2-X)N_(X) film having acharacteristic of variable electrical resistance using the spatteringwith a target of TiO₂ in a gaseous environment of N₂/O₂/Ar bycontrolling properly a gas flow ratio therebetween.

The Fourth Embodiment

The fourth embodiment according to the present invention element and thepresent invention method (properly referred to as the present embodimenthereinafter) will be described in detail below with reference to FIG. 12to FIG. 15. Here, a detailed description for a process which duplicatesthat of the first embodiment is properly omitted with mentioning thateffect.

FIG. 12 is a cross sectional pattern diagram showing the presentinvention element according to the present embodiment. The presentinvention element according to the present embodiment comprises aconfiguration that a lower electrode wiring 51 and an upper electrodewiring 54 are formed on a base substrate 55, and a variable resistorbody 53 as a memory material body is formed between the upper and thelower electrodes, wherein a bump electrode material 52 comprised of anelectrically conductive material is connected to the lower electrode 51,and the bump electrode material 52 is connected to the upper electrode54 via the variable resistor body 53, as shown in FIG. 12.

Next, the manufacturing method for the present invention elementaccording to the present embodiment will be described in detail below,as an example for the case of applying to a memory cell of 1R type asshown in FIG. 2. FIG. 13 and FIG. 14 are views showing manufacturingprocesses for the present invention element according to the presentembodiment, as shown by FIG. 13A to FIG. 14G in order of eachmanufacturing process (Those are separated into two views forconvenience' sake due to page space). In FIG. 13 and FIG. 14, a crosssectional pattern diagram along the X-X′ dashed line, that is to say,along the upper electrode wiring TE in FIG. 2 for showing the memorycell array of the 1R configuration, and a cross sectional patterndiagram along the Y-Y′ dashed line therein, that is to say, along thelower electrode wiring BE are shown at the left side and the right siderespectively therein.

First, a base insulating film 65 is to be formed on a semiconductorsubstrate 66 where peripheral circuits and the like (not shown) areproperly formed. According to the present embodiment as well as thefirst embodiment, after depositing the BPSG film 65 with the filmthickness of 1500 nm, a surface thereof is flattened by polishing thesurface of the BPSG film 65 using the CMP method to be the thickness of800 nm on a top surface of the semiconductor substrate 66. Next, amaterial film (a first electrode film) 61 to be a lower electrode wiringis to be deposited thereon. According to the present embodiment, a Tifilm of 5 nm thickness, a TiN film of 20 nm thickness, an AlCu film of200 nm thickness, another Ti film of 5 nm thickness, and another TiNfilm of 100 nm thickness are to be deposited in order using thespattering method respectively, as the multilayer structure ofTiN/Ti/Al—Cu/TiN/Ti. Moreover, an SiN film (a first insulating film) 67is to be deposited using the CVD method with the thickness of 150 nm onthe material film 61 to be the lower electrode wiring. Next, the lowerelectrode wiring is to be formed as shown in FIG. 13A, by etching theSiN film 67 with a resist as a mask (not shown) patterned as the lineand space (L/S) shape shown as the lower electrode wiring BE in FIG. 2using the photolithography method, by removing the resist thereafter,and by etching the material film 61 to be the lower electrode wiringusing the SiN film 67 as another mask thereafter.

Next, a TiN film (an electrode film for a bump electrode material) 62 asone example for a material film to be a bump electrode material is to bedeposited using the spattering method with the thickness of 40 nm overthe surface thereof, as shown in FIG. 13B. In this case, it is able toform the thickness of the TiN film 62 along a sidewall of the lowerelectrode 61 as approximately 20 nm for example.

Next, a process using the etch back is to be performed until the TiNfilm 62 on the base insulating film 65 and on the SiN film 67 iscompletely removed. The TiN film 62 is retained along the sidewalls ofthe lower electrode 61 and of the SiN film 67 by such the process, asshown in FIG. 13C.

Next, an SiO₂ film (a second insulating film) 68 is to be depositedusing the CVD method with the thickness of 600 nm over the surfacethereof, as shown in FIG. 13D.

Next, the SiO₂ film 68 is to be flattened and a part of the TiN film 62is to be exposed by polishing the SiO₂ film 68 using the CMP method tothe top surface level of the TiN film 62, as shown in FIG. 14E. Here,the flattening method is not limited to the CMP method, and it may bealso available to use any proper flattening technology including such asthe spin-on method, the spin-on method combined with the etch backmethod, or the like.

Next, a TiO₂ film 63 as one example for a variable resistor body is tobe formed by thermally oxidizing the exposed part of the bump electrodematerial 62 comprised of the TiN film in the atmosphere including oxygenat the temperature of between 250 and 450° C., as shown in FIG. 14F.

Next, a material film (a second electrode film) 64 to be an upperelectrode wiring is to be deposited over the surface thereof. Accordingto the present embodiment, a TiN film of 20 nm thickness, an AlCu filmof 200 nm thickness, a Ti film of 5 nm thickness, and another TiN filmof 100 nm thickness are to be deposited in order using the spatteringmethod respectively, as the multilayer structure of TiN/Ti/Al—Cu/TiN.Next, an upper electrode wiring 64 is to be formed by etching thematerial film 64 to be the upper electrode wiring with a resist as amask (not shown) patterned as the line and space (L/S) shape shown asthe upper electrode wiring TE in FIG. 2, using the photolithographymethod. Moreover, an interlayer insulating film 69 is to be depositedthereafter, and then a contact wiring (not shown) and a metal wiring(not shown) are to be formed for the upper electrode wiring 64 and thelower electrode wiring 61 respectively, as shown in FIG. 14G.

According to the configuration regarding the present embodiment, thereis provided the configuration that the upper electrode wiring 54 and thebump electrode material 52 are to be connected via the variable resistorbody 53, and then the bump electrode material 52 is to be connected tothe lower electrode 51 at the sidewall thereof. According to such thevariable resistive element formed thereby, it becomes able to reduce thearea of the contact surface between the variable resistor body and anyof the electrodes compared with that of the conventional configurations,as well as the above mentioned each of the embodiments.

FIG. 15 is a plane pattern diagram of the variable resistive elementaccording to the present embodiment compared with a variable resistiveelement of a conventional configuration. FIG. 15A shows the one of theconventional configuration, and FIG. 15B shows the configurationaccording to the present embodiment. Here, the configuration as shown inFIG. 15A is similar to that shown in FIG. 5A.

According to the variable resistive element regarding the presentembodiment, there is provided the configuration that the bump electrodematerial is to be formed only at an outside region of the sidewall of alower electrode wiring 125, and such the bump electrode material is tobe connected to an upper electrode wiring 126. And then a region S3 (ashaded area in the figure) as the cross point region between such thebump electrode material and the upper electrode wiring 126 becomes to bethe electrically contributing region of the variable resistor body.

The region S3 has the linear shape with the width of at least the filmthickness of the bump electrode material, however, it is able to reducean area of such the region compared with the region S1 regarding theconventional variable resistive element. Moreover, it is able to formthe bump electrode material by using the self-aligned process, and thenit is able to change arbitrarily such the area by controlling the filmthickness thereof.

That is to say, it is able to reduce a contact area according to theconfiguration regarding the present embodiment compared with the contactarea of the conventional configuration, as well as the configuration ofthe above mentioned each of the embodiments. Thus, it becomes able toreduce the current consumption, and it becomes possible to manufacturethe memory element reproducibly with the stable switching operationwithout occurring the programming impossible, by configuring anonvolatile memory device using such the element.

Here, the variable resistor body is formed by oxidizing the exposed partof the bump electrode material 62 according to the present embodiment,however, it may also available to form a variable resistor body onto thetop surface of the bump electrode material 62 by depositing a TiO₂ film(variable resistor body film) for example as the material film forvariable resistor body, as above mentioned in the third embodiment.

The Fifth Embodiment

The fifth embodiment according to the present invention element and thepresent invention method (properly referred to as the present embodimenthereinafter) will be described in detail below with reference to FIG.16. Here, a detailed description for a process which duplicates that ofthe first embodiment is properly omitted with mentioning that effect.

According to the above mentioned each of the embodiments, there isdescribed as one example for the case of applying to the memory cell of1R type, however, a memory cell is not limited thereto. Regarding thepresent embodiment, a variable resistive element and its manufacturingmethod in the case of being applied to a memory cell of 1T/1R type willbe described in detail below as another example.

FIG. 16 is a view showing manufacturing processes for the presentinvention element according to the present embodiment, as shown by FIG.16A to FIG. 16H in order of each manufacturing process.

First, a selective transistor T is to be formed on a semiconductorsubstrate 81 in accordance with the following heretofore knownprocesses, as shown in FIG. 16A. That is to say, the selectivetransistor T is to be formed on the semiconductor substrate 81 that anelement isolation region 82 is formed, which is comprised of a gateinsulating film 83, a gate electrode 84, a drain region 85 and a sourceregion 86 as diffusion layers, and then a base interlayer insulatingfilm 87 is to be formed thereunto. According to the present embodiment,after depositing a BPSG film with a film thickness of 1200 nm therefor,a surface thereof is to be flattened by polishing the surface of theBPSG film using the so-called CMP method until the thickness thereofbecomes to be 400 nm on the gate electrode 84.

Next, a contact plug 88 is to be formed for connecting between a lowerelectrode 89 and the drain region 85, as shown in FIG. 16B. Such thecontact plug 88 is to be formed in accordance with the followingheretofore known processes of: etching the base interlayer insulatingfilm 87 with a resist as a mask patterned using the photolithographymethod; opening a part to be a contact hole 88 reaching the drain region85 in the selective transistor T; depositing an electrically conductivepolysilicon film thereunto; removing completely the electricallyconductive polysilicon film on the base interlayer insulating film 87 bypolishing it using the CMP method; and retaining the electricallyconductive polysilicon film only at an inside of the contact hole 88.

Next, a lower electrode 89 comprised of a TiN film is to be formed bydepositing the TiN film (a first electrode film) using the spatteringmethod to be a thickness of 150 nm, and by patterning it using thephotolithography method.

Next, an SiO₂ film (a first insulating film) 90 is to be deposited usingthe CVD method with the thickness of 600 nm over the surface thereof,and then a surface thereof is to be flattened by polishing the SiO₂ film90 on the lower electrode 89 to be a thickness of 250 nm. Here, theflattening method is not limited to the CMP method, and it may beavailable to use any proper flattening technology including such as thespin-on method, the spin-on method combined with the etch back method,or the like. And then an open part 91 reaching the lower electrode 89 isto be formed as shown in FIG. 16C thereafter, by patterning the SiO₂film 90 using the photolithography method.

Next, a TiN film (an electrode film for a bump electrode material) 92 asone example for a material film to be a bump electrode material is to bedeposited using the spattering method with the thickness of 40 nm overthe surface thereof, as shown in FIG. 16D. In this case, it is able toform the TiN film 92 along a sidewall at an inside of the open part 91with a thickness of approximately 20 nm for example. And then an SiO₂film 93 is to be deposited using the CVD method with a thickness of 600nm over the surface thereof.

Next, the SiO₂ film 93 is to be flattened and the TiN film 92 is to beexposed by polishing the SiO₂ film 93 using the CMP method to a topsurface level of the TiN film 92. And then a bump electrode material 92comprised of the TiN film is to be formed by removing the TiN film 92 onthe SiO₂ film 90 except that inside the open part 91 using the etch backmethod thereafter, as shown in FIG. 16E.

Next, a TiO₂ film 94 as one example for a variable resistor body is tobe formed by thermally oxidizing an exposed part of the bump electrodematerial 92 comprised of the TiN film in the atmosphere including oxygenat a temperature of between 250 and 450° C., as shown in FIG. 16F.

Next, a TiN film (a second electrode film) 95 as one example for amaterial film to be an upper electrode wiring is to be deposited overthe surface thereof. According to the present embodiment, a TiN film isto be deposited using the spattering method with a film thickness of 150nm. And then as shown in FIG. 16G, a variable resistive element R is tobe formed, which is comprised of the upper electrode 95, the variableresistor body 94, and the lower electrode 89 connected to the bumpelectrode material 92, by processing the upper electrode 95 comprised ofthe TiN film, such as by patterning therefor with using thephotolithography method.

Next, an SiO₂ film 96 as an interlayer insulating film on the variableresistive element R is to be deposited using the CVD method, and then asshown in FIG. 16H, a bit wiring 99 for electrically connecting to theupper electrode 95 via a contact plug 97, and a source wiring 100 forelectrically connecting to the source region 86 via a contact plug 98are to be formed thereafter.

According to such the variable resistive element formed thereby, itbecomes able to reduce an area of a contact surface between the variableresistor body and any of the electrodes compared with that of theconventional configurations. The following is a detailed description inthis regard with reference to the drawings.

FIG. 17 is a plane pattern diagram of the variable resistive elementaccording to the present embodiment compared with a variable resistiveelement of a conventional configuration, in the case of using the memorycell of 1T/1R type. FIG. 17A shows the one of the conventionalconfiguration, and FIG. 17B shows the configuration according to thepresent embodiment.

In the case of the conventional configuration, an area of anelectrically contributing region of the variable resistor bodycorresponds to the area of either one electrode of an upper electrodeand a lower electrode regarding the structure shown in FIG. 37 forexample, and corresponds to an area of an open part formed between anupper and a lower electrodes regarding the structure shown in FIG. 39.That is to say, a region of an open part 127 specified by a workdimension is almost coincident with an electrically contributing regionS4 (a shaded area in the figure) of the variable resistor body, as shownin FIG. 17A.

On the contrary, according to the variable resistive element regardingthe present embodiment, a region S5 (a shaded area in the figure)becomes to be the electrically contributing region of the variableresistor body, which is an overlapping part between such the bumpelectrode material and the upper electrode or the lower electrode,because the bump electrode material is to be formed along the insideregion of the open part 128 as shown in FIG. 17B. Moreover, the regionS5 has a square annular shape with a width of at least a film thicknessof the bump electrode material, and it is able to reduce the areacompared with the region S4 according to the conventional variableresistive element. Further, it is able to form the bump electrodematerial by using the self-aligned process, and then it is able tochange arbitrarily such the area by controlling the film thicknessthereof. Furthermore, it is also able to obtain the similar effectregardless of the planar shape of the bump electrode material, such as arectangular annular shape, a round annular shape, or the like, based onthe shape of the open part.

According to the present embodiment, there is described the method inwhich the bump electrode material is formed at the inside of the openpart, however, it may be also able to comprise a configuration asanother modified example that a bump electrode material is to be formedat a sidewall of a lower electrode by performing the processes as wellas that of the fourth embodiment.

The Sixth Embodiment

The sixth embodiment according to the present invention element and thepresent invention method (properly referred to as the present embodimenthereinafter) will be described in detail below with reference to FIG.18. Here, a detailed description for a process which duplicates that ofthe fifth embodiment is properly omitted with mentioning that effect.

FIG. 18 is a view showing manufacturing processes for the presentinvention element according to the present embodiment, as shown by FIG.18A to FIG. 18G in order of each manufacturing process.

First, a selective transistor T is to be formed on a semiconductorsubstrate 101 by performing the processes as well as that of the fifthembodiment, as shown in FIG. 18A. That is to say, the selectivetransistor T is to be formed on the semiconductor substrate 101 that anelement isolation region 102 is formed, which is comprised of a gateinsulating film 103, a gate electrode 104, a drain region (a firstelectrode film) 105 and a source region 106 as diffusion layers, andthen a base interlayer insulating film (a first insulating film) 107 isto be formed thereunto. According to the present embodiment, afterdepositing a BPSG film with a film thickness of nm therefor, a surfacethereof is to be flattened by polishing the surface of the BPSG filmusing the so-called CMP method until the thickness thereof becomes to be400 nm on the gate electrode 104.

Next, an open part A as a contact hole reaching the drain region 105 isto be formed by etching the base interlayer insulating film 107 with aresist as a mask patterned using the photolithography method, as shownin FIG. 18B.

Next, a TiN film (an electrode film for a bump electrode material) 108as one example for a material film to be a bump electrode material is tobe deposited using the spattering method with a thickness of 20 nm overthe surface thereof. According to the present embodiment, the thicknessof the TiN film 108 formed at a sidewall of the open part A is to beapproximately 20 nm. And then an SiO₂ film 109 is to be deposited usingthe CVD method with a thickness of 600 nm over the surface thereof, asshown in FIG. 18C.

Next, the SiO₂ film 109 is to be flattened and the TiN film 108 is to beexposed by polishing the SiO₂ film 109 using the CMP method to a topsurface level of the TiN film 108. And then a bump electrode material108 comprised of the TiN film is to be formed by removing the TiN film108 on the SiO₂ film 107 except that inside the open part A using theetch back method thereafter, as shown in FIG. 18D.

Next, a TiO₂ film 110 as one example for a variable resistor body is tobe formed by thermally oxidizing an exposed part of the bump electrodematerial 108 comprised of the TiN film in the atmosphere includingoxygen at a temperature of between 250 and 450° C., as shown in FIG.18E.

Next, a TiN film (a second electrode film) as one example for a materialfilm to be an upper electrode wiring is to be deposited over the surfacethereof. According to the present embodiment, a TiN film is to bedeposited using the spattering method with a film thickness of 150 nm.And then as shown in FIG. 18F, a variable resistive element R is to beformed, which is comprised of the upper electrode 111, the variableresistor body 110, and a lower electrode connected to the bump electrodematerial 108, by processing the upper electrode 111 comprised of the TiNfilm, such as by patterning therefor with using the photolithographymethod. That is to say, according to the present embodiment, there isprovided a configuration in that the drain region 105 in the transistorT assumes a role as the lower electrode.

Next, an SiO₂ film 112 as an interlayer insulating film on the variableresistive element R is to be deposited using the CVD method, and then asshown in FIG. 18G, a bit wiring 115 for electrically connecting to theupper electrode 111 via a contact plug 113, and a source wiring 116 forelectrically connecting to the source region 106 via a contact plug 114are to be formed thereafter.

According to such the configuration as well as that of the fifthembodiment, an overlapping part between such the bump electrode materialand the upper electrode or the lower electrode becomes to be anelectrically contributing region of the variable resistor body, becausethe bump electrode material is to be formed along the inside of the openpart. Such the region corresponds to a region S5 as shown in FIG. 17B.Such the region has a square annular shape with a width of at least afilm thickness of the bump electrode material and it is able to reducethe area compared with the region S4 according to the conventionalvariable resistive element. Moreover, it is able to form the bumpelectrode material by using the self-aligned process, and then it isable to change arbitrarily such the area by controlling the filmthickness thereof. Further, it is also able to obtain the similar effectregardless of the planar shape of the bump electrode material, such as arectangular annular shape, a round annular shape, or the like, based onthe shape of the open part.

The Seventh Embodiment

The seventh embodiment according to the present invention element andthe present invention method (properly referred to as the presentembodiment hereinafter) will be described in detail below with referenceto FIG. 19 to FIG. 24. Here, a detailed description for a process whichduplicates that of the first embodiment is properly omitted withmentioning that effect.

FIG. 19 is a cross sectional view showing the present invention elementaccording to the present embodiment. The present invention elementaccording to the present embodiment comprises a configuration that alower electrode wiring 301 and an upper electrode wiring 304 are formedon a base substrate 305, and then a variable resistor body 303 as amemory material body is formed between the upper and the lowerelectrodes, wherein a bump electrode material 302 comprised of anelectrically conductive material is connected to the lower electrode301, and the variable resistor body 303 is formed on an apical part ofthe bump electrode material 302, as shown in FIG. 19.

Next, the manufacturing method for a variable resistive elementaccording to the present embodiment will be described in detail below,as an example for the case of applying to a memory cell of 1R type. FIG.20 to FIG. 22 are views showing manufacturing processes for the presentinvention element according to the present embodiment, as shown by FIG.20A to FIG. 221 in order of each manufacturing process (Those areseparated into three views for convenience' sake due to page space). InFIG. 20 to FIG. 22, a cross sectional pattern diagram along the X-X′dashed line, that is to say, along the upper electrode wiring TE in FIG.2 for showing the memory cell array of the 1R configuration, and a crosssectional pattern diagram along the Y-Y′ dashed line therein, that is tosay, along the lower electrode wiring BE are shown at the left side andthe right side respectively therein. Moreover, FIG. 23 is a planepattern diagram showing a pattern layout of an open part WBE to be usedin a manufacturing process as shown in FIG. 20C.

First, a base insulating film 315 is to be formed on a semiconductorsubstrate 316 where peripheral circuits and the like (not shown) areproperly formed. According to the present embodiment as well as thefirst embodiment, after depositing the BPSG film 315 with a filmthickness of 1500 nm, a surface thereof is flattened by polishing asurface of the BPSG film 315 using the CMP method to be a thickness of800 nm on a top surface of the semiconductor substrate 316. Next, amaterial film (a first electrode film) 311 to be a lower electrodewiring is to be deposited thereon. According to the present embodiment,a Ti film of 5 nm thickness, a TiN film of 20 nm thickness, an AlCu filmof 200 nm thickness, another Ti film of 5 nm thickness, and another TiNfilm of 105 nm thickness are to be deposited in order using thespattering method respectively, as the multilayer structure ofTiN/Ti/Al—Cu/TiN/Ti. Next, a lower electrode wiring 311 is to be formedas shown in FIG. 20A, by etching the material film 311 to be the lowerelectrode wiring with a resist as a mask (not shown) patterned as theline and space (L/S) shape shown as the lower electrode wiring BE inFIG. 2 using the photolithography method. Moreover, an SiO₂ film 317 isto be deposited using the CVD method with a thickness of 600 nm over thesurface thereof.

Next, such the surface is to be flattened by polishing the SiO₂ film 317using the CMP method to a top surface level of the lower electrodewiring 311. Moreover, an SiN film (a first insulating film) 318 is to bedeposited using the CVD method with a thickness of 150 nm over thesurface thereof, as shown in FIG. 20B.

Next, an open part 319 is to be formed for between the adjacent patternof the SiN film 318 as shown in FIG. 20C, by etching the SiN film 318with a resist as a mask (not shown in FIG. 20) patterned with an openpart of pattern shape shown as a region WBE surrounded by a dashed linein FIG. 23, using the photolithography method. In FIG. 23, a BE patternis the configuration as similar to that of the lower electrode wiring BEas shown in FIG. 2, and the open part pattern WBE is the pattern to beextended toward the similar direction of the lower electrode wiring BE,wherein both sides at the long side are to be arranged on a region ofany adjacent two of the lower electrode wirings BE respectively.Moreover, the open part pattern WBE is to be arranged iteratively, withtwice the pitch of the lower electrode wirings BE, and in parallel tothe lower electrode wiring BE. Here, the both sides at the long side(interfaces at the long side) of the open part pattern WBE are notrequired to be on central lines of the lower electrode wirings BErespectively, and they may exist anywhere as long as they are on eachregion of the lower electrode wirings BE respectively.

Next, a TiN film (an electrode film for a bump electrode material) 312as a material film to be a bump electrode material is to be depositedusing the spattering method with a thickness of 40 nm over the surfacethereof, as shown in FIG. 20D. In this case, it is able to form the TiNfilm along an inner side surface at an inside of the open part 319 witha thickness of 20 nm for example. Here, such the TiN film 312 is to beformed along the open part 319, and the inside of the open part 319 isnot to be filled therewith.

Next, a process using the etch back is performed for the TiN film 312 tobe removed completely from both surfaces of the insulating film 318 andthe insulating film 317. Hence, the TiN film 312 is to be retained onlyalong the sidewall at the inside of the open part 319 by such theprocess, as shown in FIG. 21E. Thus, a bump electrode material 312comprised of the TiN film connected to the lower electrode wiring 311 isto be formed by such the process.

Next, an SiO₂ film (a second insulating film) 320 is to be depositedusing the CVD method with a thickness of 600 nm over the surfacethereof.

Next, the SiO₂ film 320 is to be flattened and an apical part of the TiNfilm 312 is to be exposed by polishing the SiO₂ film 320 using the CMPmethod to a top surface level of the SiN film 318, as shown in FIG. 21G.And then as a result of such the process, the insulating film 318 andthe insulating film 320 become to be alternately arranged withsandwiching the bump electrode material 312 thereby, as shown in FIG.21G as well.

Next, a TiO₂ film 313 is to be formed by thermal oxidation in anatmosphere including oxygen at a temperature of between 250 and 450° C.as one example for a variable resistor body formed by oxidizing anexposed apical part of the bump electrode material 312 comprised of theTiN film, as shown in FIG. 21H. According to the present embodiment, thevariable resistor body is to be the TiO₂ film, however, it is alsopossible to form a TiO_(2-x)N_(x) film having a characteristic ofvariable electrical resistance by controlling properly an oxidationcondition, such as an oxidation temperature, an oxygen concentration, orthe like. Moreover, according to the present embodiment, the variableresistor body is formed by thermally oxidizing the bump electrodematerial, however, it may be available to use another oxidation methodas well as the above mentioned other embodiments, such as the oxidationin the oxygen plasma, the ozone oxidation, or the like. Or, it may bealso available to deposit directly onto a bump electrode material byusing the CVD method or the spattering method.

Next, a material film (a second electrode film) 314 to be an upperelectrode wiring is to be deposited over the surface thereof. Accordingto the present embodiment, a TiN film of 20 nm thickness, an AlCu filmof 200 nm thickness, a Ti film of 5 nm thickness, and another TiN filmof 100 nm thickness are to be deposited in order using the spatteringmethod respectively, as the multilayer structure of TiN/Ti/Al—Cu/TiN.Next, an upper electrode wiring 314 is to be formed by etching thematerial film 314 to be the upper electrode wiring, the variableresistor body 313 and the bump electrode material 312, with a resist asa mask (not shown) patterned as the line and space (L/S) shape shown asthe upper electrode wiring TE in FIG. 2, using the photolithographymethod. Moreover, an interlayer insulating film 321 is to be depositedthereafter, and then a contact wiring (not shown) and a metal wiring(not shown) are to be formed for the upper electrode wiring 314 and thelower electrode wiring 311 respectively, as shown in FIG. 221. Here,according to the present embodiment for such the processes, the variableresistor body 313 and the bump electrode material 312 are also removedin addition to the upper electrode wiring 314, for preventing anyadjacent pair of the BE wirings from shorting out due to the bumpelectrode material 312 formed along an inside of the open part patternWBE as shown in FIG. 23. However, it may be also possible to etch onlythe upper electrode wiring 314 in the process for the upper electrodewiring as shown in FIG. 221 if at least a partial region of the bumpelectrode material 312 and the variable resistor body 313 is removed bypatterning using the photolithography method and etching for example,which are retained at an arbitrary region except a memory cell arraywherein none of the BE wirings are comprised.

According to such the variable resistive element formed thereby, itbecomes able to reduce an area of a contact surface between the variableresistor body and any of the electrodes compared with that of theconventional configurations. The following is a detailed description inthis regard with reference to the drawings.

FIG. 24 is a plane pattern diagram of the variable resistive elementaccording to the present embodiment compared with a variable resistiveelement of a conventional configuration. FIG. 24A shows the one of theconventional configuration, and FIG. 24B shows the configurationaccording to the present embodiment. Here, the configuration as shown inFIG. 24A is similar to that shown in FIG. 5A and FIG. 15A.

According to the variable resistive element regarding the presentembodiment, there is provided the configuration that the bump electrodematerial is to be formed only at a partial region of an interface sidefor the open part pattern WBE as shown in FIG. 23 in a region on a lowerelectrode wiring 129, and it is to be electrically connected to thelower electrode wiring. And then a region S6 (the shaded area in thefigure) as a cross point region between such the bump electrode materialand an upper electrode wiring 130 becomes to be an electricallycontributing region of the variable resistor body.

The region S6 has a linear shape with a width of at least the filmthickness of the bump electrode material, however, it is able to reducean area compared with the region S1 regarding the conventional variableresistive element. Moreover, it is able to form such the bump electrodematerial by using the self-aligned process, and then it is able tochange arbitrarily such the area by controlling the film thicknessthereof.

That is to say, it is able to reduce a contact area according to theconfiguration regarding the present embodiment compared with the contactarea of the conventional configuration, as well as the configuration ofthe above mentioned each of the embodiments. Thus, it becomes able toreduce the current consumption, and it becomes possible to manufacturethe memory element reproducibly with the stable switching operationwithout occurring the programming impossible, by configuring thenonvolatile memory device using such the element. Moreover, it becomesable to reduce the contract area further than that of the abovementioned first to the fourth embodiments wherein the contact area istwo of the linear shape for one variable resistive element, because thecontact area according to the configuration regarding the presentembodiment is only one linear shape for one variable resistive element,by adding the photolithography process using the open part pattern WBEand the etching process.

According to the present embodiment, the insulating film 317 is to bethe SiO₂ film and the insulating film 318 is to be the SiN film as to bedissimilar materials therebetween, because of ensuring an etchingselectivity for the insulating film 317 at the period of the etchingprocess for the insulating film 318 as shown in FIG. 20C. However, itmay be available to use an SiN film for the insulating film 317, and anSiO₂ film for the insulating film 318. Or, it may be also applicablewith combining properly films of dissimilar materials from insulatingmaterial alternatives including other insulating materials except theSiO₂ film and the SiN film. On the contrary, it is possible to use asimilar material film for such the insulating films 317 and 318, such asthe similar SiO₂ film for example, however, it is required to controlthe etching of the insulating film 318 for controlling a decrease infilm thickness of the insulating film 317, and then it is morepreferable to choose a different material therefrom.

Ditto, the insulating film 320 is to be the SiO₂ film according to thepresent embodiment, however, it may be available to use an SiN film oranother insulating material film. However, it is more preferable to usea different material from that for the insulating film 318, for ensuringa polishing selectivity of the insulating film 320 for the insulatingfilm 318 at the period of the CMP process therefor as shown in FIG. 21G.

Moreover, according to the present embodiment as well as the otherembodiment, the material film 311 for the lower electrode wiring is tobe the multilayer structure of TiN/Ti/Al—Cu/TiN/Ti, and the materialfilm 312 for the bump electrode material is to be the TiN film. However,the film thickness for the TiN as the uppermost layer of the lowerelectrode wiring 311 is to be set with taking into consideration thedecrease in film thickness thereof, because of occurring such thedecrease in film thickness due to an over etching for such the TiN asthe uppermost layer thereof at the period of the etching process for theTiN film 312 as shown in FIG. 21E. On the contrary, it is also possibleto modify easily the manufacturing method to be such as a combination ofdissimilar materials between the material of the uppermost layer of thelower electrode wiring 311 and the material film for the bump electrodematerial.

Further, the process for forming the variable resistor body film 313according to the present embodiment is to be as shown in FIG. 21H,however, it is also possible to moodily easily such the process to beafter that as shown in FIG. 20C. That is to say, it may be available toform a TiO₂ film to be a variable resistor body on an exposed surface ofthe lower electrode wiring 311 using the thermal oxidation method afterthe process as shown in FIG. 20C, and then to perform the followingprocesses from FIG. 20D. As a result, the process as shown in FIG. 21Hbecomes unnecessary. In such a case, there is provided a configurationin that a variable resistor body is to be formed between a bumpelectrode material and a lower electrode wiring, and the bump electrodematerial is to be connected to an upper electrode wiring.

The Eighth Embodiment

The eighth embodiment according to the present invention element and thepresent invention method (properly referred to as the present embodimenthereinafter) will be described in detail below with reference to FIG. 25to FIG. 27. Here, a detailed description for a process which duplicatesthat of the seventh embodiment is properly omitted with mentioning thateffect.

FIG. 25 is a cross sectional view showing the present invention elementaccording to the present embodiment. The present invention elementaccording to the present embodiment comprises a configuration that alower electrode wiring 331 and an upper electrode wiring 334 are formedon a base substrate 335, and then a variable resistor body 333 as amemory material body is formed between the upper and the lowerelectrodes, wherein a bump electrode material 332 comprised of anelectrically conductive material is connected to the upper electrode334, and the bump electrode material 332 and the lower electrode 331 arefacing via the variable resistor body 333, as shown in FIG. 25.

Next, the manufacturing method for a variable resistive elementaccording to the present embodiment will be described in detail below,as an example for the case of applying to a memory cell of 1R type. FIG.26 and FIG. 27 are views showing manufacturing processes for the presentinvention element according to the present embodiment, as shown by FIG.26A to FIG. 27G in order of each manufacturing process (Those areseparated into two views for convenience' sake due to page space). InFIG. 26 and FIG. 27, a cross sectional pattern diagram along the X-X′dashed line, that is to say, along the upper electrode wiring TE in FIG.2 for showing the memory cell array of the 1R configuration, and a crosssectional pattern diagram along the Y-Y′ dashed line therein, that is tosay, along the lower electrode wiring BE are shown at the left side andthe right side respectively therein.

First, by performing the processes as completely similar to that of theseventh embodiment as shown to FIG. 20C, a lower electrode wiring (afirst electrode film) 341 processed using a pattern of lower electrodewiring BE and an SiO₂ film 347 implanted between each of the lowerelectrode wirings 341 are to be formed onto a base insulating film 345on a semiconductor substrate 346, as shown in FIG. 26A. Moreover, anopen part (a first open part) 349 is to be formed thereunto. Regarding afirst insulating film processed using a pattern of open part WBE(corresponds to the insulating film 348 as shown in FIG. 26, and theinsulating film 318 as shown in FIG. 20), the SiN film is to be usedaccording to the seventh embodiment, however, such the film is to be anAl₂O₃ film 348 according to the present embodiment. That is to say, theAl₂O₃ film 348 is to be deposited using the spattering method with athickness of 150 nm over the surface thereof, and then an open part 349is to be formed for between the adjacent pattern of the Al₂O₃ film 348,by etching such the film with a resist as a mask patterned with the openpart pattern WBE using the photolithography method.

Next, an SiO₂ film (a dummy film) 350 as an insulating material is to bedeposited using the CVD method with a thickness of 25 nm over thesurface thereof, as shown in FIG. 26B. In this case, it is able to formthe SiO₂ film 350 along an inner side surface of the open part 349 witha thickness of 20 nm for example. Here, such the SiO₂ film 350 is to beformed along the open part 349, and an inside of the open part 349 isnot to be filled therewith.

Next, a process using the etch back is to be performed until the SiO₂film 350 on the insulating film 348 and on the insulating film 347 iscompletely removed. Hence, the SiO₂ film 350 is retained only along aside surface of the open part 349 (or a sidewall of the Al₂O₃ film 348)by such the process, as shown in FIG. 26C. And then an SiN film (asecond insulating film) 351 is to be deposited using the CVD method witha thickness of 600 nm over the surface thereof.

Next, the SiN film 351 is to be flattened and an apical part of the SiO₂film 350 formed along an inner side surface of the open part 349 is tobe exposed by polishing the SiN film 351 using the CMP method to a topsurface level of the Al₂O₃ film 348, as shown in FIG. 26D. And then as aresult of such the process, the insulating film 348 and the insulatingfilm 351 become to be alternately arranged with sandwiching the SiO₂film 350 thereby, as shown in FIG. 26D as well.

Next, only the SiO₂ film 350 is to be removed selectively for the Al₂O₃film 348, the SiN film 351 and for the lower electrode wiring 341, byusing the wet etching method with a hydrofluoric acid, as shown in FIG.27E. According to such the process, only a partial region on a topsurface of the lower electrode wiring 341 is to be exposed by athickness of the SiO₂ film 350 formed along an inner side surface of theopen part 349, and then an open part (a second open part) 352 is to beformed with a height of a thickness of the Al₂O₃ film 348 or that of theSiN film 351.

Next, a TiO₂ film 343 is to be formed by thermal oxidation in anatmosphere including oxygen at a temperature of between 250 and 450° C.as one example for a variable resistor body formed by oxidizing anexposed part on a top surface of the lower electrode wiring 341 at aninside of the open part 352, as shown in FIG. 7F. According to thepresent embodiment, the variable resistor body is to be the TiO₂ film,however, it is also possible to form a TiO_(2-x)N_(x) film having acharacteristic of variable electrical resistance by controlling properlyan oxidation condition, such as an oxidation temperature, an oxygenconcentration, or the like. Moreover, according to the presentembodiment, the variable resistor body is formed by thermally oxidizinga partial region of the lower electrode wiring 341, however, it may bealso available to use another oxidation method as well as the abovementioned other embodiments, such as the oxidation in the oxygen plasma,the ozone oxidation, or the like.

Next, a material film (a second electrode film) 344 to be an upperelectrode wiring is to be deposited over the surface thereof, as shownin FIG. 27G. According to the present embodiment, a TiN film of 20 nmthickness, an AlCu film of 200 nm thickness, a Ti film of 5 nmthickness, and another TiN film of 100 nm thickness are to be depositedin order using the spattering method respectively, as the multilayerstructure of TiN/Ti/Al—Cu/TiN. The material film 344 to be the upperelectrode wiring is to be implanted into the open part 352 by such theprocess, so that a bump electrode material 342 comprised of a materialfilm 344 to be an upper electrode wiring is to be formed. Here, theupper electrode wiring 344 is shown as a shadow area using dots and thebump electrode material 342 is shown as a shaded area in FIG. 27G forconvenience' sake, however, such the parts are the identical materialfilm to be deposited at the identical process according to the presentembodiment.

Next, an upper electrode wiring 344 is to be formed by etching thematerial film 344 to be the upper electrode wiring, the variableresistor body and the bump electrode material 342 with a resist as amask (not shown) patterned as the line and space (L/S) shape shown asthe upper electrode wiring TE in FIG. 2, using the photolithographymethod. Moreover, an interlayer insulating film 353 is to be depositedthereafter, and then a contact wiring (not shown) and a metal wiring(not shown) are to be formed for the upper electrode wiring 344 and thelower electrode wiring 341 respectively.

According to the configuration regarding the present embodiment, thereis provided a configuration that the bump electrode material 332 and thelower electrode 331 are facing via the variable resistor body 333, and abump electrode material 332 is to be connected to the upper electrode334, as shown in FIG. 25. Therefore, the plane pattern diagram becomesto be similar to that of the seventh embodiment as shown in FIG. 24B,showing the configuration in that the bump electrode material is to beformed only at a partial region of an interface side for the open partpattern WBE as shown in FIG. 23, and then it becomes to be electricallyconnected to the upper electrode wiring. Therefore, the region S6 (theshaded area in FIG. 24) as the cross point region between such the bumpelectrode material and the lower electrode wiring 130 becomes to be theelectrically contributing region of the variable resistor body.

According to such the variable resistive element formed thereby, it isable to reduce an area of a contact surface between the variableresistor body and any of the electrodes compared with that of theconventional configuration, as similar to that according to the seventhembodiment. Thus, it becomes able to reduce a current consumption, andit becomes possible to manufacture a memory element reproducibly with astable switching operation without occurring a programming impossible,by configuring a nonvolatile memory device using such the element.

According to the present embodiment, the dummy film formed on the openpart 349 is to be the SiO₂ film 350, however, it is not limited thereto,and it may be also available to use another material film. Moreover,such the dummy film is not required to be the insulating material filmbecause it is to be removed at the process as shown in FIG. 27E, and itmay be an electrically conductive material film as well. However, it isdesirable to use a material to be able to remove by etching selectivelyfor the insulating film 348, the insulating film 351 and for the lowerelectrode wiring 341. Moreover, such the selective etching is to be thewet etching by using the acid treatment according to the presentembodiment, however, the present invention is not limited thereto.

Moreover, the insulating film 347, the insulating film 348 and theinsulating film 351 are not limited to the materials according to thepresent embodiment, as well as that according to the seventh embodiment.However, it is more preferable to select a material individually, forsuch as the insulating film 348 different from that for the insulatingfilm 347, and for the insulating film 351 different from that for theinsulating film 348. As another example for taking into considerationthe above mention, it may be also available to comprise a configurationin that the insulating film 348 is to be an SiN film, the insulatingfilm 351 is to be an SiO₂ film, and the insulating film 350 is replacedwith an amorphous Si (α-Si) film as a non-insulated material, and thenthe α-Si film 350 is to be removed by dry etching using a reactive ionetching (RIE) method at the process as shown in FIG. 27E.

Further, as a modified example of the present embodiment, it may be alsopossible to modify easily the process as implanting the inside of theopen part 352 by depositing a material film for a bump electrodematerial over the surface thereof, after the process as shown in FIG.27E, and then forming the bump electrode material at the inside of theopen part 352 by using the etch back or the CMP. Next, a variableresistor body is to be formed at an apical part of the bump electrodematerial by oxidizing a top surface thereof, and then an electrode filmfor comprising an upper electrode is to be deposited thereafter. In sucha case, the bump electrode material is to be connected to the lowerelectrode, and the variable resistor body is to be formed at the apicalpart of the bump electrode material. Hence, there is provided aconfiguration regarding a structure of cross sectional shape therefor asbecoming to be similar to that in FIG. 19.

Furthermore, as another modified example of the present embodiment, itmay be also possible to modify easily the process as implanting theinside of the open part 352 by depositing a material film for a bumpelectrode material over the surface thereof, after the process as shownin FIG. 27F, and then forming the bump electrode material at the insideof the open part 352 by using the etch back or the CMP. Next, anelectrode film for comprising an upper electrode is to be deposited ontoa top surface of the bump electrode material thereafter. In such a case,there is provided a configuration in that a variable resistor body is tobe formed at a bottom edge of the bump electrode material, and then theupper electrode is to be formed at an upper part of the bump electrodematerial. Hence, there is provided a configuration regarding a structureof cross sectional shape therefor as becoming to be similar to that inFIG. 25.

The Ninth Embodiment

The ninth embodiment according to the present invention element and thepresent invention method (properly referred to as the present embodimenthereinafter) will be described in detail below with reference to FIG. 28to FIG. 32. Here, a detailed description for a process which duplicatesthat of the seventh embodiment is properly omitted with mentioning thateffect.

FIG. 28 is a cross sectional view showing the present invention elementaccording to the present embodiment: FIG. 28A is a cross sectional viewin a parallel direction of an upper electrode wiring 404; and FIG. 28Bis a cross sectional view in a parallel direction of a lower electrodewiring 401. The present invention element according to the presentembodiment comprises a configuration that the lower electrode wiring 401and the upper electrode wiring 404 are formed on a base substrate 405,and then a variable resistor body 403 as a memory material body isformed between the upper and the lower electrodes, wherein a first bumpelectrode material 402 comprised of an electrically conductive materialis connected to the lower electrode 401, a second bump electrodematerial 406 comprised of an electrically conductive material isconnected to the upper electrode 404, the first bump electrode material402 and the second bump electrode material 406 are facing via thevariable resistor body 403, as shown in FIG. 28.

Next, the manufacturing method for a variable resistive elementaccording to the present embodiment will be described in detail below,as an example for the case of applying to a memory cell of 1R type. FIG.29 and FIG. 30 are views showing manufacturing processes for the presentinvention element according to the present embodiment, as shown by FIG.29A to FIG. 30G in order of each manufacturing process (Those areseparated into two views for convenience' sake due to page space). InFIG. 29 and FIG. 30, a cross sectional pattern diagram along the X-X′dashed line, that is to say, along the upper electrode wiring TE in FIG.2 for showing the memory cell array of the 1R configuration, and a crosssectional pattern diagram along the Y-Y′ dashed line therein, that is tosay, along the lower electrode wiring BE are shown at the left side andthe right side respectively therein. Moreover, FIG. 31 is a planepattern diagram showing a pattern layout of an open part WTE to be usedin a manufacturing process as shown in FIG. 29B.

First, by performing the processes as completely similar to that of theseventh embodiment as shown to FIG. 21H, a lower electrode wiring (afirst electrode film) 411 processed using a pattern of lower electrodewiring BE and then an SiO₂ film 417 implanted between each of the lowerelectrode wirings 411 are to be formed onto a base insulating film 415on a semiconductor substrate 416, as shown in FIG. 29A. Moreover, afirst bump electrode material 412 is to be formed thereunto, which isconnected to a partial region of a top surface of the lower electrodewiring 411, and comprised of a TiN film (an electrode film for a firstbump electrode material). And then a TiO₂ film 413 as one example for avariable resistor body is to be formed by oxidizing an exposed apicalpart of such the first bump electrode material 412.

Here, in the present invention element according to the presentembodiment, the two bump electrode materials are facing via the variableresistor body as above mentioned. As described later, such the bumpelectrode materials are formed by extending along a sidewall of aninsulating film comprising individual open parts (an inner sidewall ofan open part) respectively. For clarifying a relation between such thebump electrode material and a location in which such the bump electrodematerial is formed, there is described only for the present embodimentin that an insulating film comprising an open part for a first bumpelectrode material to be formed (a first open part) is referred to as afirst insulating film, and another insulating film comprising an openpart for a second bump electrode material to be formed (a second openpart) is referred to as a second insulating film. And then an insulatingfilm to be deposited for an object of filling the open part afterforming the bump electrode material is referred to as a fillerinsulating film. That is to say, a insulating film to be deposited foran object of filling the inside of the first open part after forming thefirst bump electrode material is referred to as a first fillerinsulating film, and another insulating film to be deposited for anobject of filling the inside of the second open part after forming thesecond bump electrode material is referred to as a second fillerinsulating film.

That is to say, the SiN film 318 according to the seventh embodimentcorresponds to the first insulating film according to the presentembodiment, and the open part 319 therein corresponds to the first openpart according to the present embodiment. Moreover, the first bumpelectrode material 412 according to the present embodiment is to beformed so as to extend upward along an inner sidewall of such the firstopen part.

Moreover, an insulating film for filling the first open part afterforming the first bump electrode material corresponds to the abovementioned first filler insulating film, which corresponds to the SiO₂film 320 according to the seventh embodiment.

Next, an Al₂O₃ film (a second insulating film) 418 is to be depositedusing the spattering method with a thickness of 150 nm over the surfacethereof. And then an open part (a second open part) 419 is to be formedfor between the adjacent pattern of the Al₂O₃ film 418 as shown in FIG.29B, by etching the Al₂O₃ film 418 with a resist as a mask (not shown inFIG. 29) patterned with an open part of pattern shape shown as a regionWTE surrounded by a dashed line in FIG. 31, using the photolithographymethod. In FIG. 31, a TE pattern is the configuration as similar to thatof the upper electrode wiring TE as shown in FIG. 2, and the open partpattern WTE is the pattern to be extended toward the similar directionof the upper electrode wiring TE, wherein both sides at the long sideare to be arranged on a region of any adjacent two of the upperelectrode wirings TE respectively. Moreover, the open part pattern WTEis to be arranged iteratively, with twice the pitch of the upperelectrode wirings TE, and in parallel to the upper electrode wiring TE.Here, the both sides at the long side (interfaces at the long side) ofthe open part pattern WTE are not required to be on central lines of theupper electrode wirings TE respectively, and they may exist anywhere aslong as they are inside the upper electrode wirings TE respectively.

Next, a TiN film (an electrode film for a second bump electrodematerial) 420 as a material film to be a second bump electrode materialis to be deposited using the spattering method with a thickness of 40 nmover the surface thereof, as shown in FIG. 29C. In this case, it is ableto form the TiN film 420 along an inner side surface at an inside of theopen part 419 with a thickness of 20 nm for example. Here, such the TiNfilm 420 is to be formed along the open part 419, and the inside of theopen part 419 is not to be filled therewith.

Next, a process using the etch back is performed for the TiN film 420 tobe removed completely from a surface of the insulating film 418. Hence,the TiN film 420 is to be retained only at an inner side surface of theopen part 419, as shown in FIG. 29D. Thus, the second bump electrodematerial 420 comprised of the TiN film is to be formed by such theprocess.

Next, an inside of the open part 419 is to be filled by depositing anSiO₂ film (a second filler insulating film) 421 thereunto using the CVDmethod with a thickness of 600 nm over the surface thereof.

Next, a surface of the SiO₂ film 421 is to be flattened and an apicalpart of the TiN film 420 as the second bump electrode material is to beexposed by polishing the SiO₂ film 421 using the CMP method to a topsurface level of the Al₂O₃ film 418, as shown in FIG. 30F.

Next, a material film (a second electrode film) 414 to be an upperelectrode wiring is to be formed over the surface thereof. According tothe present embodiment, a TiN film of 20 nm thickness, an AlCu film of200 nm thickness, a Ti film of 5 nm thickness, and another TiN film of100 nm thickness are to be deposited in order using the spatteringmethod respectively, as the multilayer structure of TiN/Ti/Al—Cu/TiN.Next, an upper electrode wiring 414 is to be formed by etching thematerial film 414 to be the upper electrode wiring and the second bumpelectrode material 420 with a resist as a mask (not shown) patterned asthe line and space (L/S) shape shown as the upper electrode wiring TE inFIG. 2, using the photolithography method. Moreover, an interlayerinsulating film 422 is to be deposited thereafter, and then a contactwiring (not shown) and a metal wiring (not shown) are to be formed forthe upper electrode wiring 414 and the lower electrode wiring 411respectively, as shown in FIG. 30G.

According to such the variable resistive element formed thereby, itbecomes able to reduce an area of a contact surface between the variableresistor body and any of the electrodes compared with that of theconventional configurations. The following is a detailed description inthis regard with reference to the drawings.

FIG. 32 is a plane pattern diagram of the variable resistive elementaccording to the present embodiment compared with a variable resistiveelement of a conventional configuration. FIG. 32A shows the one of theconventional configuration, and FIG. 32B shows the configurationaccording to the present embodiment. Here, the configuration as shown inFIG. 32A is similar to those shown in FIG. 5A, FIG. 15A and FIG. 24A.

According to the variable resistive element regarding the presentembodiment, there is provided a configuration that the first bumpelectrode material is to be formed only at a partial region of aninterface side for the open part pattern WBE as shown in FIG. 23 in aregion on a lower electrode wiring 131, and it is to be electricallyconnected to the lower electrode wiring 131 (a region 133 surrounded bya dashed line in FIG. 32), and then the second bump electrode materialis to be formed only at a partial region of an interface side for theopen part pattern WTE as shown in FIG. 31 in a region on a upperelectrode wiring 132, and it is to be electrically connected to theupper electrode wiring 132 (a region 134 surrounded by a dashed line inFIG. 32). Therefore, a region S7 (a shaded area in the figure) as across point region between the region 133 for the first bump electrodematerial and the region 134 for the second bump electrode materialbecomes to be an electrically contributing region of the variableresistor body.

The region S7 has the rectangular shape with one side length of at leastthe film thickness of the first bump electrode material and the otherside length of at least the film thickness of the second bump electrodematerial, however, it is able to reduce an area of such the regioncompared with the region S1 regarding the conventional variableresistive element. Moreover, it is able to form the first and the secondbump electrode materials by using the self-aligned process, and then itis able to change arbitrarily such the area by controlling the filmthickness thereof.

That is to say, it is able to reduce a contact area according to theconfiguration regarding the present embodiment compared with the contactarea of the conventional configuration, as well as the configuration ofthe above mentioned each of the embodiments. Thus, it becomes able toreduce the current consumption, and it becomes possible to manufacturethe memory element reproducibly with the stable switching operationwithout occurring the programming impossible, by configuring thenonvolatile memory device using such the element. Moreover, it becomesable to reduce the contract area more than that of the seventh and theeighth embodiments, by adding the photolithography process for the openpart pattern WTE and the etching process.

Here, according to the present embodiment, the insulating films underthe upper electrode wiring 414 are to be the Al₂O₃ film 418 and the SiO₂film 421, however, it is not limited thereto, and it may be available touse other material films therefor respectively. However, it is morepreferable to use a different material for the insulating film 418 fromthat for the insulating film 421, for ensuring a polishing selectivityof the insulating film 421 for the insulating film 418 at the period ofthe CMP process therefor as shown in FIG. 30F.

Moreover, according to the present embodiment, the variable resistorbody film 413 is to be formed at the apical part of the first bumpelectrode material 412 at the process as shown in FIG. 29A, however, itis also available to adopt easily a modified example in that such thefilm is to be deposited after the process for the Al₂O₃ film 418. FIG.33 is a view showing manufacturing processes for the present modifiedexample, as shown by FIG. 33A to FIG. 33D in order of each manufacturingprocess. In FIG. 33, a cross sectional pattern diagram along the X-X′dashed line, that is to say, along the upper electrode wiring TE in FIG.2 for showing the memory cell array of the 1R configuration, and a crosssectional pattern diagram along the Y-Y′ dashed line therein, that is tosay, along the lower electrode wiring BE are shown at the left side andthe right side respectively therein.

First, by performing the processes as completely similar to that of theseventh embodiment as shown to FIG. 21G, a lower electrode wiring (afirst electrode film) 411 processed using a pattern of lower electrodewiring BE and an SiO₂ film 417 implanted between each of the lowerelectrode wirings 411 are to be formed onto a base insulating film 415on a semiconductor substrate 416, as shown in FIG. 33A. Moreover, afirst bump electrode material 412 is to be formed thereunto, which isconnected to a partial reason of a top surface of the lower electrodewiring 411, and comprised of a TiN film (an electrode film for a firstbump electrode material).

Next, an Al₂O₃ film (a second insulating film) 423 is to be depositedusing the spattering method with a thickness of 150 nm over the surfacethereof. And then an open part (a second open part) 424 is to be formedfor between the adjacent pattern of the Al₂O₃ film 423 as shown in FIG.33B, by etching the Al₂O₃ film 423 with a resist as a mask (not shown inFIG. 33) patterned with an open part of pattern shape shown as theregion WTE surrounded by the dashed line in FIG. 31, using thephotolithography method.

Next, a TiO₂ film 425 is to be formed by thermal oxidation in anatmosphere including oxygen at a temperature of between 250 and 450° C.as one example for a variable resistor body formed by oxidizing anexposed apical part on a top surface of the first bump electrodematerial 412 at an inside of the open part 424, as shown in FIG. 33C.

Hereinafter, by performing the processes as similar to that as shownfrom FIG. 29C through FIG. 30G, a second bump electrode material 426comprised of a TiN film (an electrode film for a second bump electrodematerial) along an inner side surface of the open part 424, an SiO₂ film(a second filler insulating film) 427 for filling the open part (thesecond open part) 424 formed on the variable resistor body 425 betweenthe adjacent pair of the second bump electrode materials 426, an upperelectrode wiring (a second electrode film) 428 and an interlayerinsulating film 429 are to be formed, as shown in FIG. 33D. Thus, itbecomes able to form a variable resistive element according to themodified example regarding the present embodiment.

Here, regarding the present embodiment, it is desirable to add a processfor removing at least a partial region of the first bump electrodematerial 412 by patterning using the photolithography method and theetching method, which are retained at an arbitrary region except amemory cell array wherein none of the BE wirings are comprised, forpreventing any adjacent pair of the BE wirings from shorting out due tothe first bump electrode material 412 formed along the inside of theopen part pattern WBE as shown in FIG. 23. Such the process may be addedat any one of the steps after forming the first bump electrode material412 but before the process as shown in FIG. 30E.

Moreover, according to the present embodiment regarding the process asshown in FIG. 30G, the second bump electrode material 420 are alsoetched to be removed in addition to the upper electrode wiring 414, forpreventing any adjacent pair of the TE wirings from shorting out due tothe second bump electrode material 420 formed along the inside of theopen part pattern WTE as shown in FIG. 36. However, it may be alsopossible to etch only the upper electrode wiring 414 in the process forthe upper electrode wiring, if at least a partial region of the secondbump electrode material 420 is removed by patterning using thephotolithography method and the etching method for example, which areretained at an arbitrary region except a memory cell array, wherein noneof the TE wirings are comprised.

Further, according to the present embodiment, the bump electrodematerial formed by performing the processes as completely similar tothat of the seventh embodiment as shown to FIG. 21G is to be the firstbump electrode material, however, it is also possible to be easily abump electrode material formed by performing the processes as completelysimilar to that of the second embodiment as shown to FIG. 11E. In such acase, an area of an electrically contributing region of a variableresistor body becomes to be two times larger than that of the regiondescribed with reference to FIG. 32 because the area is separated intotwo places. However, it becomes able to be unnecessary to add the abovementioned process for removing the first bump electrode materialretained at an arbitrary region except a memory cell array, because thefirst bump electrode material is not formed along an inside of an openpart pattern WBE.

The Tenth Embodiment

The tenth embodiment according to the present invention element and thepresent invention method (properly referred to as the present embodimenthereinafter) will be described in detail below with reference to FIG. 34to FIG. 37. Here, a detailed description for a process which duplicatesthat of the first embodiment is properly omitted with mentioning thateffect.

FIG. 34 is a cross sectional view showing the present invention elementaccording to the present embodiment. The present invention elementaccording to the present embodiment comprises a configuration that alower electrode wiring 431 and an upper electrode wiring 434 are formedon a base substrate 435, and then a variable resistor body 433 as amemory material body is formed between the upper and the lowerelectrodes, wherein a bump electrode material 432 comprised of anelectrically conductive material is connected to the lower electrode431, and the variable resistor body 433 is formed on an apical part ofthe bump electrode material 432, as shown in FIG. 34. Moreover,different from the variable resistive element according to the abovementioned each of the embodiments, the bump electrode material 432 is tobe extended in a plane parallel direction to the base substrate 435, anda contact surface between the variable resistor body 433 and the upperelectrode film 434 is to be formed so as to be approximatelyperpendicular to the base substrate 435.

Next, the manufacturing method for a variable resistive elementaccording to the present embodiment will be described in detail below,as an example for the case of applying to a memory cell of 1R type. FIG.35 and FIG. 36 are views showing manufacturing processes for the presentinvention element according to the present embodiment, as shown by FIG.35A to FIG. 36F in order of each manufacturing process (Those areseparated into two views for convenience' sake due to page space). InFIG. 35 and FIG. 36, a cross sectional pattern diagram along the X-X′dashed line, that is to say, along the upper electrode wiring TE in FIG.2 for showing the memory cell array of the 1R configuration, and a crosssectional pattern diagram along the Y-Y′ dashed line therein, that is tosay, along the lower electrode wiring BE are shown at the left side andthe right side respectively therein.

First, a base insulating film 445 is to be formed on a semiconductorsubstrate 446 that peripheral circuits and the like (not shown) areproperly formed. According to the present embodiment as well as thefirst embodiment, after depositing the BPSG film 445 with the filmthickness of 1500 nm, a surface thereof is flattened by polishing thesurface of the BPSG film 445 using the CMP method to be the thickness of800 nm on a top surface of the semiconductor substrate 446. Next, amaterial film (an electrode film for a bump electrode material) 442 tobe a bump electrode material, a material film (a first electrode film)441 to be a lower electrode wiring, and then an SiO₂ film (a firstinsulating film) 447 are to be deposited in order thereon. According tothe present embodiment, a TiN film 442 is to be deposited using thespattering method with a thickness of 20 nm for the material film to bethe bump electrode material, and then for the material film 441 to be alower electrode wiring, a Ti film of 5 nm thickness, a TiN film of 20 nmthickness, an AlCu film of 200 nm thickness, another Ti film of 5 nmthickness, and another TiN film of 100 nm thickness are to be depositedin order using the spattering method respectively, as the multilayerstructure of TiN/Ti/Al—Cu/TiN/Ti. Moreover, the SiO₂ film 447 is to bedeposited using the CVD method with the thickness of 150 nm thereunto.Next, a lower electrode wiring 441 is to be formed as shown in FIG. 35A,by etching the SiO₂ film 447 with a resist as a mask (not shown)patterned as the line and space (L/S) shape shown as the lower electrodewiring BE in FIG. 2, using the photolithography method, and by etchingthe material film 441 to be the lower electrode wiring using the SiO₂film 447 as another mask thereafter.

Next, an SiO₂ film (a second insulating film) 448 is to be depositedusing the CVD method with a thickness of 150 nm over the surfacethereof.

Next, a process using the etch back is to be performed until the SiO₂film 448 on the TiN film 442 is completely removed, as shown in FIG.35C. The SiO₂ film 448 is retained as a sidewall spacer shape at a sidesurface of the lower electrode wiring 441 by such the process, that is,a sidewall film is to be formed.

Next, a bump electrode material 442 comprised of the TiN film andconnected to the lower electrode wiring 441 is to be formed at a bottompart of the SiO₂ film 448 of the sidewall spacer shape, by etching theTiN film 442 with using the SiO₂ film 447 and the SiO₂ film 448 of thesidewall spacer shape as masks, as shown in FIG. 35D.

Next, a TiO₂ film 443 is to be formed by thermal oxidation in anatmosphere including oxygen at a temperature of between 250 and 450° C.as one example for a variable resistor body formed by oxidizing anexposed apical part of the bump electrode material 442 comprised of theTiN film, as shown in FIG. 36E. According to the present embodiment, thevariable resistor body is to be the TiO₂ film, however, it is alsopossible to form a TiO_(2-x)N_(x) film having a characteristic ofvariable electrical resistance by controlling properly an oxidationcondition, such as an oxidation temperature, an oxygen concentration, orthe like. Moreover, according to the present embodiment, the variableresistor body is formed by thermally oxidizing the bump electrodematerial, however, it may be available to use another oxidation methodas well as the above mentioned other embodiments, such as the oxidationin the oxygen plasma, the ozone oxidation, or the like. Or, it may bealso available to deposit directly onto a bump electrode material byusing the CVD method or the spattering method.

Next, a material film (a second electrode film) 444 to be an upperelectrode wiring is to be deposited over the surface thereof. Accordingto the present embodiment, a TiN film of 20 nm thickness, an AlCu filmof 200 nm thickness, a Ti film of 5 nm thickness, and another TiN filmof 100 nm thickness are to be deposited in order using the spatteringmethod respectively, as the multilayer structure of TIN/Ti/Al—Cu/TiN.Next, an upper electrode wiring 444 is to be formed by etching thematerial film 444 to be the upper electrode wiring with a resist as amask (not shown) patterned as the line and space (L/S) shape shown asthe upper electrode wiring TE in FIG. 2, using the photolithographymethod. Moreover, an interlayer insulating film 449 is to be depositedthereafter, and then a contact wiring (not shown) and a metal wiring(not shown) are to be formed for the upper electrode wiring 444 and thelower electrode wiring 441 respectively, as shown in FIG. 36F.

According to such the variable resistive element formed thereby, itbecomes able to reduce an area of a contact surface between the variableresistor body and any of the electrodes compared with that of theconventional configurations. The following is a detailed description inthis regard with reference to the drawings.

FIG. 37 is a plane pattern diagram of the variable resistive elementaccording to the present embodiment compared with a variable resistiveelement of a conventional configuration. FIG. 37A shows the one of theconventional configuration, and FIG. 37B shows the configurationaccording to the present embodiment. Here, the configuration as shown inFIG. 37A is similar to that shown in FIG. 5A, FIG. 15A, FIG. 24A andFIG. 32A.

According to the variable resistive element regarding the presentembodiment, there is provided a configuration in that the bump electrodematerial connected to the lower electrode wiring 135 is extended in aplane parallel direction to a position to be alienated outside with adistance of the film thickness of the sidewall shape for the insulatingfilm 448 from an interface side for the lower electrode wiring 135, andthen a region S8 (a shaded area in the figure) as a cross point regionbetween such the bump electrode material and an upper electrode wiring136 becomes to be an electrically contributing region of the variableresistor body. The region S8 in FIG. 37 has a linear shape with a widthof at least the film thickness of the bump electrode material in aperpendicular direction to the page (in a vertical direction to thesubstrate surface), however, it is able to reduce an area of such theregion compared with the region S1 regarding the conventional variableresistive element. Moreover, it is able to form the bump electrodematerial by using the self-aligned process, and then it is able tochange arbitrarily such the area by controlling a thickness of a film tobe deposited onto the base substrate. Further, it is possible to setsuch the film thickness thinner than the film thickness of the lowerelectrode wiring 135.

That is to say, it is able to reduce a contact area according to theconfiguration regarding the present embodiment compared with the contactarea of the conventional configuration, as well as the configuration ofthe above mentioned each of the embodiments. Thus, it becomes able toreduce the current consumption, and it becomes possible to manufacturethe memory element reproducibly with the stable switching operationwithout occurring the programming impossible, by configuring anonvolatile memory device using such the element.

Here, according to the above mentioned present embodiment, there isdescribed as one example for the case of applying to a variableresistive element comprising a memory cell of 1R type, however, it isalso available to apply the variable resistive element according to thepresent invention to a memory cell of 1T/1R type. That is to say, it ispossible to apply the variable resistive element easily to a memory cellof 1T/1R type, by pattering the insulating film 447 and the materialfilm 441 to be the lower electrode wiring so as to be an isolatedrectangular shape at the process as shown in FIG. 35A, by pattering thematerial film 444 to be the upper electrode wiring so as to be anisolated rectangular shape as well at the process as shown in FIG. 36F,and forming properly a selective transistor, a contact plug forelectrically connecting to the lower electrode, and wirings, such as asource wiring, a bit wiring, or the like, in the memory cell, using themethod as similar to that for the fifth embodiment.

FIG. 37C is a plane pattern diagram showing a configuration to beapplied to a variable resistive element comprising a memory cell of1T/1R type. According to such the variable resistive element, there isprovided a configuration in that the bump electrode material connectedto a lower electrode wiring 137 of an isolated rectangular shape isextended in a plane parallel direction to a position to be alienatedoutside with the distance of the film thickness of the sidewall shapefor the insulating film 448 from the lower electrode wiring 137, andthen a region S9 (a shaded area in the figure) as a cross point regionbetween such the bump electrode material and an upper electrode wiring138 becomes to be an electrically contributing region of the variableresistor body. The region S9 in FIG. 37 is to be formed with an annularshape so as to surround the lower electrode, and has a width of at leastthe film thickness of the bump electrode material in a perpendiculardirection to the page (in a vertical direction to the substratesurface). Moreover, it is able to form the bump electrode material byusing the self-aligned process, and then it is able to changearbitrarily such the area by controlling a film thickness of a film tobe deposited onto the base substrate. Further, it is possible to setsuch the film thickness thinner than the film thickness of the lowerelectrode wiring 137.

The Eleventh Embodiment

The eleventh embodiment according to the present invention element andthe present invention method (properly referred to as the presentembodiment hereinafter) will be described in detail below with referenceto FIG. 38 to FIG. 41. Here, a detailed description for a process whichduplicates that of the first embodiment is properly omitted withmentioning that effect.

FIG. 38 is a cross sectional view showing the present invention elementaccording to the present embodiment. The present invention elementaccording to the present embodiment comprises a configuration that alower electrode wiring 451 and an upper electrode wiring 454 are formedon a base substrate 455, and then a variable resistor body 453 as amemory material body is formed between the upper and the lowerelectrodes, wherein a bump electrode material 452 comprised of anelectrically conductive material is connected to the upper electrode454, and the variable resistor body 453 is formed on an apical part ofthe bump electrode material 452, as shown in FIG. 38. Moreover, as wellas the variable resistive element according to the tenth embodiment, thebump electrode material 452 is to be extended in a plane paralleldirection to the base substrate 455, and a contact surface between thevariable resistor body 453 and the lower electrode 451 is to be formedso as to be approximately perpendicular to the base substrate 455.

Next, the manufacturing method for a variable resistive elementaccording to the present embodiment will be described in detail below,as an example for the case of applying to a memory cell of 1R type. FIG.39 and FIG. 40 are views showing manufacturing processes for the presentinvention element according to the present embodiment, as shown by FIG.39A to FIG. 40G in order of each manufacturing process (Those areseparated into two views for convenience' sake due to page space). InFIG. 39 and FIG. 40, a cross sectional pattern diagram along the X-X′dashed line, that is to say, along the upper electrode wiring TE in FIG.2 for showing the memory cell array of the 1R configuration, and a crosssectional pattern diagram along the Y-Y′ dashed line therein, that is tosay, along the lower electrode wiring BE are shown at the left side andthe right side respectively therein. Moreover, FIG. 41 is a planepattern diagram showing a pattern layout of a wiring pattern RBE to beused in a manufacturing process as shown in FIG. 39A.

First, a base insulating film 465 is to be formed on a semiconductorsubstrate 466 where peripheral circuits and the like (not shown) areproperly formed. According to the present embodiment as well as thefirst embodiment, after depositing the BPSG film 465 with the filmthickness of 1500 nm, a surface thereof is flattened by polishing thesurface of the BPSG film 465 using the CMP method to be the thickness of800 nm on a top surface of the semiconductor substrate 466. Next, amaterial film (an electrode film for a bump electrode material) 462 tobe a bump electrode material, and then an SiN film (a dummy film) 467are to be deposited in order thereupon. According to the presentembodiment, a TiN film 462 is to be deposited using the spatteringmethod with a thickness of 20 nm for the material film to be the bumpelectrode material, and then the SiN film 467 is to be deposited usingthe CVD method with a thickness of 300 nm thereunto.

Next, a bump electrode material 462 is to be formed as shown in FIG.39A, by etching the SiN film 467 with a resist as a mask (not shown inFIG. 39) patterned as a wiring pattern RBE shown in FIG. 41, using thephotolithography method, and by etching the TiN film 462 using the SiNfilm 467 as another mask thereafter. In FIG. 41, a BE pattern is theconfiguration as similar to that of the lower electrode wiring BE asshown in FIG. 2, and the wiring pattern RBE (a shadow area in thefigure) is defined as a region where the BE pattern is reversed.

Next, a TiO₂ film 463 is to be formed by thermal oxidation in anatmosphere including oxygen at a temperature of between 250 and 450° C.as one example for a variable resistor body formed by oxidizing anexposed apical part of the bump electrode material 462 comprised of theTiN film. According to the present embodiment, the variable resistorbody is to be the TiO₂ film, however, it is also possible to form aTiO_(2-x)N_(x) film having a characteristic of variable electricalresistance by controlling properly an oxidation condition, such as anoxidation temperature, an oxygen concentration, or the like. Moreover,according to the present embodiment, the variable resistor body isformed by thermally oxidizing the bump electrode material, however, itmay be available to use another oxidation method as well as the abovementioned other embodiments, such as the oxidation in the oxygen plasma,the ozone oxidation, or the like. Next, a material film (a firstelectrode film) 461 to be a lower electrode wiring is to be depositedthereafter, as shown in FIG. 39B. According to the present embodiment, aTi film of 5 nm thickness, a TiN film of 20 nm thickness, an AlCu filmof 200 nm thickness, another Ti film of 5 nm thickness, and another TiNfilm of 100 nm thickness are to be deposited in order using thespattering method respectively, as the multilayer structure ofTiN/Ti/Al—Cu/TiN/Ti.

Next, a surface thereof is to be flattened by polishing the materialfilm 461 to be a lower electrode wiring using the CMP method to a topsurface level of the SiN film 467. Moreover, a lower electrode wiring461 is to be formed by the etch back for the material film 461 to be thelower electrode wiring with reducing the film thickness thereof, andthen a stepped part 468 is to be formed between the lower electrodewiring 461 and the SiN film 467, as shown in FIG. 39C. According to thepresent embodiment, the stepped part 468 with a height of 100 nm is tobe formed, by etching further 100 nm after the surface thereof is to beflattened.

Next, an SiO₂ film (a first insulating film) 469 is to be depositedusing the CVD method with a thickness of 600 nm over the surfacethereof, as shown in FIG. 39D.

Next, the stepped part 468 is to be implanted and a surface thereof isto be flattened by polishing the SiO₂ film 469 using the CMP method to atop surface level of the SiN film 467, as shown in FIG. 40E.

Next, only the SiN film 467 is to be removed selectively for the SiO₂film 469, the lower electrode wiring 441 and for the TiN film 462, byusing the wet etching method with heated phosphoric acid, and an openpart is to be formed. And then an SiO₂ film (a second insulating film)470 of a sidewall spacer shape is to be formed at a side surface of thelower electrode wiring 461, as shown in FIG. 40F, by performing aprocess using the etch back, after depositing the SiO₂ film 470 usingthe CVD method with a thickness of 150 nm over the surface.

Next, a material film (a second electrode film) 464 to be an upperelectrode wiring is to be deposited over the surface. According to thepresent embodiment, a TiN film of 20 nm thickness, an AlCu film of 200nm thickness, a Ti film of 5 nm thickness, and another TiN film of 100nm thickness are to be deposited in order using the spattering methodrespectively, as the multilayer structure of TiN/Ti/Al—Cu/TiN. Next, anupper electrode wiring 464 is to be formed by etching the material film464 to be the upper electrode wiring and the bump electrode material 462with a resist as a mask (not shown) patterned as the line and space(L/S) shape shown as the upper electrode wiring TE in FIG. 2, using thephotolithography method. Moreover, an interlayer insulating film 471 isto be deposited thereafter, and then a contact wiring (not shown) and ametal wiring (not shown) are to be formed for the upper electrode wiring464 and the lower electrode wiring 461 respectively, as shown in FIG.40G.

According to the configuration regarding the present embodiment, it isable to form an electrically contributing region of the variableresistor body as a linear shape with a width of at least a filmthickness of the bump electrode material, as well as that according tothe tenth embodiment, and then it is able to reduce an area of such theregion compared with that regarding the conventional variable resistiveelement. Moreover, it is able to form the bump electrode material byusing the self-aligned process, and then it is able to changearbitrarily such the area by controlling a thickness of a film to bedeposited onto the base substrate. Further, it is possible to set suchthe film thickness thinner than the film thickness of the lowerelectrode wiring.

That is to say, it is able to reduce a contact area according to theconfiguration regarding the present embodiment compared with the contactarea of the conventional configuration, as well as the configuration ofthe above mentioned each of the embodiments. Thus, it becomes able toreduce the current consumption, and it becomes possible to manufacturethe memory element reproducibly with the stable switching operationwithout occurring the programming impossible, by configuring anonvolatile memory device using such the element.

According to the present embodiment, the dummy film 467 is to be the SiNfilm, however, it is not limited thereto, and it may be also availableto use any other material films properly. Moreover, such the dummy filmis not required to be the insulating material film because it is to beremoved in the manufacturing process, and it may be an electricallyconductive material film as well. However, it is desirable to use amaterial which can be removed by etching selectively for the insulatingfilm 469, the lower electrode wiring 461 and for the bump electrodematerial 462. Moreover, such the selective etching is to be the wetetching by using the acid treatment according to the present embodiment,however, the present invention is not limited thereto.

Moreover, according to the above mentioned present embodiment, there isdescribed as an example for the case of applying to a variable resistiveelement comprising a memory cell of 1R type, however, it may be alsoavailable to apply the variable resistive element according to thepresent invention to a memory cell of 1T/1R type.

Thus, according to the present invention element described following thefirst to the eleventh embodiments, it is not necessary to reduce theline width of the upper electrode or of the lower electrode, becausethere is provided the configuration in that the area of the electricallycontributing region of the variable resistor body is to be reduced byusing the bump electrode material to be connected to the upper electrodeor the lower electrode. And then according to the present inventionelement, it becomes able to avoid the problem that the wiring resistanceof the upper electrode or of the lower electrode is increased, which mayoccur in the case of solving the conventional problems by reducing theline width of the upper electrode or of the lower electrode beyond alimitation of an exposure technology using some sort of method. Thisindicates that the present invention element is more effective for thememory cell array configuration of 1R type, wherein it is required tocomprise a longer electrode wiring length corresponding to anintegration of more memory cells.

Moreover, according to the present invention element, it becomes able toavoid the problem that the wiring resistance of the upper electrode orof the lower electrode is increased, which may occur in the case ofsolving the conventional problems by forming the film thickness thinnerfor the upper electrode or for the lower electrode and by using only theside surface thereof using some sort of method. This indicates by thesame token that the present invention element is more effective for thememory cell array configuration of 1R type, wherein it is required tocomprise the longer electrode wiring length corresponding to theintegration of more memory cells.

As above mentioned, according to the variable resistive element and itsmanufacturing method of the present invention, it is able to form avariable resistor body film by a thermal processing step of oxidation asa general process in manufacturing processes for semiconductor, and thenit is not required a particular equipment for such a deposition thereof,because it is able to select a transition metal or a nitride of atransition metal element for a material film for a bump electrodematerial, and then because it is able to use an oxide of the transitionmetal element or an oxynitride of the transition metal element formed byoxidizing one end part thereof respectively as a variable resistor body.Moreover, a matching property with an existing CMOS process is high, andthen it is easy to manufacture thereof, because any novel metal is notnecessarily required as the material film for a bump electrode material.

Moreover, there is obtained an advantage that it becomes easy fordesigning processes with using a titanium based material which has beenconventionally used in general purpose in semiconductor processes, bychoosing a titanium nitride for a material film of the above mentionedbump electrode material, and by choosing a titanium oxide or a titaniumoxynitride as an oxide material or an oxynitride material of such thematerial film for the variable resistor body.

Further, there is obtained an advantage of reducing the fluctuation inresistance value regarding the variable resistor body, as an additionalfunction according to the present invention. It may be inferable that aneffect from a local filament part in the variable resistor is clearedaway according to the variable resistive element regarding the presentinvention, by reducing the area of the electrically contributing regionof the variable resistor body, and then that the fluctuation may beimproved because an intrinsic property (a property inherent to the film)of the variable resistor appears thereby, compared with the conventionalvariable resistive element in that such the local filament part effectsdominantly for the variation in resistance value, as described in thenonpatent document 2. Thus, it becomes possible to control a variationin resistance value within a further smaller range for the resistancevalue according to the variable resistive element regarding the presentinvention.

Still further, according to the above mentioned each of the embodimentsregarding the present invention, there is described the electricallycontributing region of the variable resistor body based on theexpression “linear shape” or “annular shape”, however, these are notstrictly limited as a linear shape or a rectangular annular shaperespectively. That is to say, it is also possible to modify using suchas a curve, a polygonal line, combination of those, or the like, insteadof a straight line. And even in a case of using a half circle, aU-shape, or a letter “L” shape, if it is a configuration for reducing anarea of an electrically contributing region of a variable resistor body,the effectiveness of the present invention is not negatively influencedthereby. Or, it may be also available to use a round shape or a shape ofan ellipse instead of the rectangular annular shape, or a polygoninstead of a quadrangle, and then it is also possible to modify such theannular shape to be configured with a polygonal line or a curve.

Furthermore, according to the above mentioned each of the embodimentsregarding the present invention, a control element in the memory cell of1T/1R type is to be a MOS transistor, however, even if it is to beanother control element, such as a diode element or the like, it doesnot hinder at all the application of the variable resistive elementaccording to the present invention. Moreover, it is also possible to bea memory cell comprising a configuration in that diodes are to be seriesconnected to a cross point structure region, for reducing a parasiticcurrent in the memory cell of 1R type. Such the diode generally has astructure in which it is connected to a variable resistor body as amemory material body in series outside of an upper electrode or of alower electrode, however, it may be also available to be a configurationin that a diode is to be arranged between a variable resistor body andan upper electrode, or between a variable resistor body and a lowerelectrode. Further, it is available for a diode to use a materialexhibiting such as a PN diode characteristic or a Schottky diodecharacteristic, a varistor of such as ZnO or Bi₂O₃, or the like.

Here, according to the above mentioned each of the embodiments regardingthe present invention, there is described using the TiN film for theelectrically conductive material as the bump electrode material,however, it is not limited thereto. For example, a transition metal ofsuch as Ti, Ni, Zn, V, Nb, or the like, is to be used for a bumpelectrode material, and then it is available to use an oxide of thetransition metal element formed by oxidizing one apical part thereof,for a variable resistor body. Moreover, a nitride of a transition metalelement as electrically conductive, such as ZnN, WN, or the like, is tobe used for a bump electrode material, and then it is available to usean oxide of the transition metal element or an oxynitride of thetransition metal element formed by oxidizing one apical part thereof,for a variable resistor body.

Further, in addition to such the materials, a novel metal of such as Pt,Ir, Ru, Os, Rh, Pd, or the like, a metal element of such as Al or thelike, or other sort of alloys may be also available for a material filmfor a bump electrode material. However, it is required to form avariable resistor body by using a deposition method for such the metalmaterials. Therefore, it is more preferable to use the above mentionedtransition metal or the nitride of the transition metal element aselectrically conductive for a material film for a bump electrodematerial, for leveraging an advantage as one aspect according to thepresent invention that a variable resistor body is to be formed byoxidizing one apical part of a bump electrode material.

Still further, according to the above mentioned each of the embodimentsregarding the present invention, the variable resistor body is to be theTiO₂ film, however, a variable resistor body film is not limitedthereto. For example, it is able to use an oxide of other transitionmetal elements or an oxynitride of other transition metal elementsformed by oxidizing respectively the above mentioned transition metalsor nitrides of the transition metal elements except the Ti and the TiN.Or, it is also available to form a perovskite-type oxide of such as thePCMO film or the like directly onto a bump electrode material.

Still further, according to the above mentioned each of the embodimentsregarding the present invention, the upper electrode and the lowerelectrode are to be the TiN film, or the film of multilayer structurecomprised of the TiN film, Ti film and the Al—Cu film, however, it isnot limited thereto. For example, it is possible to select arbitrarilyfrom other transition metals, an alloy including such the elements, anovel metal of such as Pt, Ir, Ru, Os, Rh, Pd, or the like, a metalelement of such as Al or the like, or other sort of alloys and the like.

Furthermore, according to the above mentioned each of the embodimentsregarding the present invention, there is described such as the titaniumnitride is to be the TiN, the titanium oxide is to be the TiO₂, thetitanium oxynitride is to be the TiO_(2-X)N_(X), or the like, however,such the description is an abbreviation, and a composition ratio foreach of the elements is not exactly defined thereby. In particular, thetitanium oxide and the titanium oxynitride can be applied as a variableresistor body to the present invention, as long as they comprise acomposition ratio for a variable resistance property therein.Furthermore, each of the described dimensions is one example fordescribing the manufacturing processes according to each of theembodiments, and it is not limited to such the dimensions.

Industrial Applicability

The variable resistive element and its manufacturing method according tothe present invention are applicable to a nonvolatile semiconductormemory device.

The invention claimed is:
 1. A variable resistive element comprising: avariable resistor body provided between two electrodes, in which anelectrical resistance of between the two electrodes is changed byapplying a voltage pulse between the two electrodes; and a bumpelectrode material making contact with either one of the two electrodesand extending toward the other one of the two electrodes, wherein thebump electrode material is extended along a sidewall of an insulatingfilm formed between the two electrodes, and formed so as to projecttoward the other one of the two electrodes with an annular or aplurally-separated linear shape, the variable resistor body is formedbetween a projecting portion of the bump electrode material and theother one of the two electrodes, and has an annular or aplurally-separated linear shape depending on a shape of the bumpelectrode material, wherein the overall shape of the variable resistorbody is annular or a plurally-separated linear shape; and the variableresistor body consists of a material formed by oxidizing the bumpelectrode material.
 2. The variable resistive element according to claim1, wherein the insulating film is formed on a lower electrode of the twoelectrodes, and the bump electrode material is extended along an outersidewall of the insulating film.
 3. The variable resistive elementaccording to claim 1, wherein a lower electrode as an electrode formedat a lower region regarding the two electrodes is a diffusion layerformed on a semiconductor substrate.
 4. The variable resistive elementaccording to claim 1, wherein the bump electrode material is formedusing a transition metal or a nitride of a transition metal element. 5.The variable resistive element according to claim 1, wherein the bumpelectrode material is a titanium nitride.
 6. The variable resistiveelement according to claim 1, wherein the variable resistor body isformed by oxidizing a part of the bump electrode material.
 7. Thevariable resistive element according to claim 1, wherein the variableresistor body is formed of an oxide of a transition metal element or anoxynitride of a transition metal element.
 8. The variable resistiveelement according to claim 7, wherein the variable resistor body is atitanium oxide or a titanium oxynitride.
 9. A manufacturing method for avariable resistive element, the variable resistive element according toclaim 1, the method comprising: a first step of forming a lowerelectrode as an electrode to be formed at a lower region regarding thetwo electrodes by depositing an electrode material onto a substrate toform a first electrode film; a second step of forming a first insulatingfilm on the lower electrode, the first insulating film having an openpart reaching a top surface of the lower electrode; a third step offorming a bump electrode material contacting to at least a partialregion of the lower electrode and extending upward along an innersidewall of the open part formed at the second step; a fourth step offorming the variable resistor body at an apical part of the bumpelectrode material by oxidizing an exposed part of the bump electrodematerial; and a fifth step of forming an upper electrode as an electrodeto be formed at an upper region regarding the two electrodes bydepositing an electrode material to form a second electrode film. 10.The manufacturing method according to claim 9, wherein the third stepcomprises steps of: forming an electrode film for a bump electrodematerial by depositing an electrically conductive material onto the openpart and the first insulating film; depositing a third insulating filmonto the electrode film for the bump electrode material; removing thethird insulating film until a top surface of the electrode film for thebump electrode material is exposed; and forming the bump electrodematerial connecting to the lower electrode inside the open part byremoving the electrode film for the bump electrode material layered at aregion other than a region on the open part.
 11. The manufacturingmethod according to claim 9, wherein the third step further comprises: asixth step of forming an electrode film for a bump electrode material bydepositing an electrically conductive material onto the open part andthe first insulating film; and a step of forming the bump electrodematerial along a sidewall of the open part by removing the electrodefilm for the bump electrode material layered on the first insulatingfilm.
 12. The manufacturing method according to claim 11, wherein thesixth step includes depositing the electrode film for the bump electrodematerial inside the open part so that a film thickness of the electrodefilm for the bump electrode material becomes thinner toward a topsurface of the lower electrode.
 13. The manufacturing method accordingto claim 12, wherein the fourth step comprises a step of forming a thirdinsulating film on the open part and the first insulating film, and thestep of forming the third insulating film includes forming the variableresistor body by oxidizing a region of the bump electrode materialformed along the sidewall of the open part at the third step, the regionhaving a thin film thickness in a vicinity of a top surface of the lowerelectrode.
 14. The manufacturing method according to claim 9, furthercomprising a step of forming the variable resistor body by forming thebump electrode material and depositing a variable resistor body materialonto at least the bump electrode material to form a variable resistorbody film.
 15. The manufacturing method according to claim 9, furthercomprising a step of forming the variable resistor body by forming thebump electrode material and oxidizing an exposed part of the bumpelectrode material.
 16. The manufacturing method according to claim 9,wherein the bump electrode material is a titanium nitride.
 17. Themanufacturing method according to claim 9, wherein the variable resistorbody is a titanium oxide or a titanium oxynitride.
 18. A manufacturingmethod for a variable resistive element, the variable resistive elementaccording to claim 1, the method comprising: a first step of forming alower electrode as an electrode to be formed at a lower region regardingthe two electrodes by depositing a first electrode film, which is to bethe lower electrode, onto a substrate, by depositing a first insulatingfilm onto the first electrode film, and by processing the firstelectrode film and the first insulating film; a second step of forming abump electrode material contacting to at least a partial region of thelower electrode and extending upward along an outer sidewall of thelower electrode and an outer sidewall of the first insulating film; athird step of forming the variable resistor body at an apical part ofthe bump electrode material; and a fourth step of forming an upperelectrode as an electrode to be formed at an upper region regarding thetwo electrodes by depositing an electrode material to layer a secondelectrode film.
 19. The manufacturing method according to claim 18,wherein the second step comprises steps of: forming an electrode filmfor a bump electrode material by depositing an electrically conductivematerial over a whole surface including a top surface of the firstinsulating film; and forming the bump electrode material along the outersidewall of the first electrode film and the outer sidewall of the firstinsulating film by removing the electrode film for the bump electrodematerial formed at a region other than the outer sidewall of the firstelectrode film and the outer sidewall of the first insulating film. 20.The manufacturing method according to claim 18, wherein the third stepcomprises steps of: depositing a second insulating film over a wholesurface including a top surface of the first insulating film; andflattening a second insulating film until a top surface of the electrodefilm for the bump electrode material is exposed.
 21. The variableresistive element according to claim 1, wherein the annular or theplurally-separated linear shaped part of the variable resistor bodycontacts with the other one of the two electrodes directly or indirectlyvia a diode.